I came at the beginning of the Reddit exodus in June and I haven’t noticed necessarily a shift to Reddit’s culture as it’s grown but more of just the general toxicity that comes along with a platform growing to a certain size.
There is a lot more trolls and likewise people who won’t engage civilly with someone who has an opposing view (because why would you when there is a good chance the other person is just a troll?). I feel like the reaction to Lemmy.world blocking piracy communities or most instances degenerating from Hexbear have shown me that.
Lemmy culture still seems to be intact. A lot of posting is still tech focused and the is still a lot of good discussion. It just seems like a lot of posts that make “Hot” on the All feed tend to be more combative or politically charged.