My favourite part of Reddit were comments. Almost every time they were better than the post itself. Yeah quality was kinda low, but you could find some meaningfull discussion or useful information. On Lemmy every post in my feed has maximum 10 comments. Where can I find more?
The fediverse (and Lemmy/kbin specifically) is both smaller than reddit and more spread out. So you aren’t as likely to find threads with thousands of comments as you would on reddit.
Reddit is estimated to have over 500,000,000 monthly active users. Meanwhile, some estimates suggest Lemmy an kbin have about 60,000 monthly active users.
And when you make a post on Lemmy, you aren’t posting to /r/gaming, with 37,300,000 subscribers and 9,500 currently online. You might be posting to https://beehaw.org/c/gaming which boasts 6,950 users per month or https://lemmy.ml/c/gaming with 942 users per month or https://lemmy.world/c/games with 1,150 users per month. Those 3 large-for-lemmy gaming communities combined see fewer users each month than reddit says is on /r/gaming right now.
There simply aren’t enough people in the same space interacting with the same content to consistently have comment sections with the depth and breadth that you’re used to.
As the other commenter said, you can seek out large comment sections by viewing federated timeline and sorting for it, but there’s no guarantee the activity will be on posts you care about.