...either I was primed by the comments I read on Reddit about the game (in general, not the specific DLC) coming across as "fake" or the writing in this DLC really was forcing a way to connect things that happened earlier in the story to later events.

Perhaps it's both.
I liked the base game + Cove DLCs because I could still go along with the supposedly "fake" stuff but here in Derek's route, I couldn't shake off how contrived things seemed. I mean, okay, maybe I can go along with a part-timer remembering their regulars even after ten years upon meeting them once again in a completely different and unrelated establishment (fine, even that's a bit lot of a stretch), but having a guy remember a specific tantrum he threw when he was six years old because his favorite older brother "ditched" a pre-planned family outing in favor of going on a date with his crush?
That must've been one indelible experience, huh.
I think I could've gone along with it more had it not been preceded by similar things in the story. For instance, the XOXO Droplets cameos were cute in the base game but the way they were brought up again in Derek's route seemed out of place. It instead came off as the story trying too hard to connect too many things that happened in the characters' shared childhood to their present.
One or two things like that is fine as part of storytelling but using it too often removes the "wow" factor (for lack of a better phrase) and makes things feel forced.
I understand that Nico bringing up Derek ditching their family outing to go with MC was a means to highlight how much Derek liked MC. Derek and MC needed all the help they could get to establish their relationship without things coming off as too "fast" or something considering they hadn't properly hung out in the ten years since (on-screen, anyway), yet I couldn't help but feel that there might have been another way to make things feel less Stepford Wives.
(Hold on. An otome game relationship banking on one summer MC and LI spent together when they were younger? Isn't that just 7'Scarlet?! HAHAHAHA)
Ahhhh, I didn't really enjoy this DLC as much as I expected to. Sometimes it also felt like they were ticking off boxes for "representation", coming off as forced/trying too hard once again, though the base game also had shades of this in some parts.
Was it absolutely necessary to spend time talking about Jorge's nonbinary significant other whom we don't even get to meet? Maybe if the MC had more time with Derek (and by association, with the Suarez family) it would've felt less out of place but honestly it was right up there with the XOXO Droplets mentions via psychic.
Anywho, one thing I did appreciate about this DLC though is that it showed another side to relationships: when you date someone, sometimes their whole family can come in as a package deal with them too. Derek's also a real sweetheart (+ beefcake) and I only wish there were more opportunities to spoil him in-game lol.
