I think I've seen this effect.
Felt a bit smug when I saw a post of r/linux talking about how the quality of the posts was so poor after the "reddit migration".
I've noticed it too that the quality of posts in certain subreddits I cared about just felt a lot more 'empty'. Which is both good and bad. Good cause Reddit got what they deserved and people stuck to their morals by dispersing to more federated communities across the web; but I also feel a tad sad that the subreddit championing a vision I want to see that took a long time to get there is now gonna leave a way pooer impression on anyone looking to join.
But eh, I'm not sure many if any people's mind on trying out Linux were decided due to a reddit post before. ( Feel free to tell me otherwise if I am wrong on feeling. )
I think my bigtest issue with Lemmy is that I waited a bit from the huge migration because it just felt so incomplete and it was such a mess to jump into but now that I finally joined it feels dead with lots of subs basically dead with only some posts from months ago like the overzealous people decided this was dead and disappeared.