Saw the same thing happen recently to a project made by friend of mine (and no, it was genuinely a cool project, and it isn't me trying to tell a personal story under a guise of it being done by a friend; I would love to take any amount of credit for it, but I had zero involvement whatsoever).

The project was basically a wordle-like game, but for chess puzzles. It was focused less on being an actual chess puzzle game (i.e., tricky chess game positions that lead to a decisive turnaround) and more on actually training to improve your blunder game (i.e., each puzzle was more of a "pick a move that isn't a blunder given a scenario from a real lichess game").

He made a post on r/chess, it gathered a small number upvotes, there were a few comments left along the lines of "omg this is so awesome, this is helping my anti-blunder skills a lot, had no idea I wanted this until I saw it." And no, I didn't leave a comment, but I upvoted the post. It didn't feel right to brigade a post with my positive comments on it as a friend, especially given how anal reddit mods can get about this in some cases.

Next thing I see, mods just removed his post with a "no promotion allowed" reasoning. The website had no ads, no paid components, not even a name/profile of my friend attached to it (so no self-promotion angle either; he is gainfully employed and isn't looking for a job). He did it purely for the love of the game, some subreddit users clearly found it helpful, and yet the mods just deleted it.

Do you participate in this community otherwise? People are generally warmer to self-promotion if it comes from someone who posts in the community in a normal way.