game design hypothesis: I think in TTRPGs, mechanics and narrative might be something that exist on a sliding scale that I can imagine like this:
Narrative [-----X-----] Mechanics
You can move the X left or right and stretch it a bit so it covers more ground, but you can't just decide that the X is now so wide that it actually covers both sides of the scale.

Examples?

Here are some games that already exist and that people tend to know, from more mechanics to less. Note that this is not a good/bad scale, I'm just trying to get a thought in my head into your heads via the medium of written words:
Warhammer 40k is a game with extreme numerical focus. It has books so thick and so hardcover that people have definitely committed acts of criminal violence with it. While there is a very developed setting and it's possible to roleplay, I suspect the actual ratio of people doing that during games is very low. The standard interaction in the game is to announce something like "my crisis battlesuits fire on the daemon brute" and then you roll and count dice for 7 minutes.

D&D is still quite far up on the mechanics side. It is more unusual to have people ONLY ever announce their mechanical interactions and nothing else, but during combat, the game does not expect you to, or reward, any interaction besides calling attacks and skills. I have been at tables where I tried my absolute best to add flair and energy by describing things and the other players were tired by my attempts to make this something that the game isn't, they just wanted to hear "I attack the spider". All that was allowed was "how do you wanna do this" when the final enemy is defeated.
During non-combat, things are a bit different. It would still be very possible to play the game like a group of text adventure people who just input their problem solution attempts, but even then, characters tend to naturally get into discussions over approaches and ideology, as well as questioning NPCs for information, so that's something.

I wouldn't say that Forged in the Dark is the exact midpoint, but it's so well-known here, and I recently said I think it's a little mechanics engine, while still being perceived by many players as primarily about narrative positioning. The games make you spend many different resources on the one hand but also describe how you do something so it works better (that's the narrative positioning), it rewards you for interacting with teammates (in aid and downtime actions) and talking to npcs (in many forms of game moves).

And then there are the many many games that people like us tend to make. I'll just point to one of my own games: The Inspectors Are In, a game in which you OSHA-inspect a fantasy dungeon. It literally comes without a resolution mechanic and is just a varied set of prompts for improvisational play. It's ALL in the interaction between the characters. No numbers will help you decide if that pirate skeleton ship is up to code. (Also, I realized that I should probably make the game cheaper now that it's been out for a while, so I just did.)

Removing the Dice and/or Narrative Positioning

I thought about the game I wanted to explore making for a few hours now. I first wrote down my wishes: I would like to give as much narrative freedom as like, a FITD or an Apocalypse Engine would give. You know, room to inhabit a character with all that entails, build a setting, argue about whether this action would work or not based on the logic of the game world and established precedence. And I would also like to have mechanics where you go "oh do I want to spend a red point now, I might need it later? Or a blue point, which is less valuable and I get it back, but it doesn't do as much? What do you think, grilla?"

That sounds exciting and doable in theory. But as I started imagining the game further in my head, I found it was so much harder to "force" that to happen with what's written. It's possible to write a game that's essentially just a board game, like Oath. Where people like Shut Up And Sit Down can draw out the fantasy of a story that is implicitly there in the work, but people like me see only the gears and the resource exchanges, not the narrative unfolding. Partially because we aren't... role-playing between the humans at the table! I really like Oath. I would love if we could just TTRPG-ify Oath and be done with it. But I don't think that's doable. At least not at my skill level, alone. If the words "TTRPG-ify Oath" just made your brain activate, please feel free to either message me with any idea you have so we can make the world a better place.

On the other hand, It's possible to write a game that's clearly an RPG, that asks players to describe things, to fill in the gaps that the game's writing intentionally leaves, where the fun is in the narrative positioning. Thorn, the game that started me on my last thought path a few days ago, is one of these. It not only starts by saying it knows that it leaves holes, it is also only 27 pages long and more than half of those are lists. It HAS done away with dice and randomness. So what's left is that you have to narratively position yourself and expend resources. You have essentially 6 different single-use resources of different kinds and their varied nature just makes it easier to think of solutions. It's not always "I hit the monster" because you packed your bags with a bunch of more interesting ideas before you set out.

The final possible iteration comes with Eat the Reich, which we played a second session of just today. Eat the Reich is lovely overall and one of the visually best-designed RPG books out there, and I'll play it several more times to form a clearer opinion. but it is also a book that comes with the least Narrative Positioning of all of these. It gives hints for roleplay stuff, but it doesn't really... put in the room to do it? Narrative positioning is really just on items (if you say you flank someone, you do it and get extra dice. That's BASICALLY it).

You don't get a bonus for exchanging a SINGLE word inside the team. There is no time that the game encourages you, mechanically, to ever interact with any NPC (besides by defeating them because they're nazis). The game also wants you to describe how you kill nazis after your dice roll is resolved, which imo always takes out a lot of the tension. You should get the bonus dice for basically creating the 'roundabout: to be continued' meme before your roll, then after you roll we find out WHO gets fucked up.

What I'm learning here

I think it's becoming clear to me that, whatever I end up writing, I need to incorporate narrative positioning into the game. To reward the players for saying how they do something, for interacting with npcs and players, in a way that can not be "farmed" infinitely. But I am still spooked by my initial analysis that, if I make it too much of a "game"-game, it will overshadow the storytelling aspect. That players will be too busy counting their coins to think about their blorbos, you know?

When I said that I don't think I could make Oath a functioning RPG, it's because I think it's got TOO MUCH game. It's SO FAR on the mechanics side, which are very very fulfilling and demanding. It's not about the theme of the game, but about how many brain cycles the players are using. Unless you are meeting with the absolutely perfectly people (which I am not presuming here), I don't think most people have the energy for this.

There's a good reason why there is no "roleplaying as your Final Fantasy 14 characters while on voice while fighting bosses" community, and it's not primarily that the player voices would not fit the characters.