Apart from the few subs that remain offline, it'll basically be back to normal. Those that do remain offline indefinitely just get forcibly reopened or recreated by admins, especially huge subreddits like /r/videos. Smaller ones just get redicted to /r/topicnew or some other creative name.
A lot of subreddits and more importantly moderators and users leave the site permanently. In order for this to happen however, there'd have to be a consensus alternative, which there isn't ATM. Otherwise, these communities are pretty much lost forever unless the mods put a message to go to X alternative service in the "subreddit is private" banner. Tbh, I don't think people are gonna stomach losing years of their lives in an instant so they'll just re create subreddits unless the mods provide an alternative.
No matter what though, they're not backing down on the effective removal of the API (still leaving the sneaky clause "you can pay us if you want but it'll be a king's ransom" for AI, even though they can just trawl the web manually lol). They'll probably announce some crappy customization features to hoodwink those who don't know what an API is and lie to them and say it's "API v2" or whatever.
I just honestly don't know how it's going to shake out and I'm scared im going to lose these communities. I don't give a single solitary fuck about Reddit the company anymore, and I never did really. I just hope all of the subreddits find a new home and don't just shrug their shoulders and say "welp, guess that's it guys".
Reddit was never going to just shut down overnight, but it's more or less done for me (barring some sudden change with the API stuff, but even then I'd make an effort to use it less). I'll keep my account around and might occasionally go to it to look up specific things or visit more niche communities that don't have much of a presence here or on other alternatives yet, but I'm done with just generally browsing reddit or providing any content for them. I'm enjoying it here and hope the boost in activity allows for continued growth and filling out of communities for more specific topics.
I'm in the same boat. I mainly used Reddit to get into new hobbies and currently it's cycling. The amount of new posts on there is staggering and I've learned a ton over the past year. I'll be unsubbing from most subreddits and using it as a tool for specific subjects. For community building, discussions, and news I think I've found a new home in Lemmy. Hopefully I can contribute and help nieche communities grow so I can leave altogether.