What sort of game would you recommend as a first to make? And, in regards to small and simple concepts, do you have a process for keeping them small and light? I have a lot of trouble trying to come up with small, simple ideas versus letting my ADHD brain go hog-wild and flesh out a full feature product, and it makes the creation of games a much scarier prospect when the ideas are so big.
Hi hi! Sorry I didn't get to this sooner, I wanted to be able to take the time to answer it properly.
For a very first game to make - do a single screen arcade game. One screen. If you made two screens and one of them isn't a title screen, you blew it. Making an early 80's style arcade game will teach you to make the most of simple mechanics and you can learn all the fundamentals of code and art design and what have you without the project getting huge. I've never done this, I've only wished I've done this
As for a process to keep scope from spiraling out of control - I wish I had this! I've just had to make a goal of keeping the minimum acceptable scope as low as possible, with the understanding that the scope is going to grow regardless.
Something that can help is to avoid going too deep on any single aspect of the game unless it's the entire point of the game - just make the minimum viable version of everything before you start getting into the weeds. Text boxes are a great example of this - you can spend forever making them cool and interactive and beautiful, but you really should just put text on the screen and move on immediately, until everything else is done. Heck, if dialogue isn't even important to the game, don't even do that much! Save it for last!
For further reading on avoiding common game dev pitfalls, I recommend the articles Derek Yu wrote on the subject: https://www.derekyu.com/makegames/
I hope that helps!