I was a huge reddit user over the years, but now I only go there for a handful of very specific subreddits. That's really it's only use anymore. It's great for that, but they are probably seeing massive decline in usage.
And the moment they basically kill 3rd party reddit apps is the day I barely touch it again.
Even smaller subreddits can be pretty terrible with bad mods.
A lot of smaller hobby subreddits are basically treated as facebook groups, with people treating it as a group for people with an interest and not a focused discussion about that interest,
Be it cars, bikes, coffee, firearms, you name it.
For hobbies I've found Tiktok is riddled with low quality content.
I suppose it really depends what you're looking for.
Discord is good but it's a chat app first and foremost and it's a pain to search for esoteric information, especially since you have to be in the server in question to even search.
Though I would also argue that one of the biggest negatives about Reddit is that you can't come back to a thread later that day or another day, if you want to get your reply head then you need to respond immediately and attain a lot of upvotes. With a forum you could respond whenever you wanted and get a discussion going. And similarly forums would allow you to avoid the echochamber effect by avoiding upvotes/downvotes as everything was chronologically ordered, so it was a much more civil affair.
But I agree that the chain-of-quotes is a positive about Reddit, which I think might be possible to implement/merge into a new forum design.