That is an interesting idea. How will your UI display comments like a chatroom when they are deeply nested? As in, a reply to a reply to a reply to a reply? I think you're going to have a difficult time with that.
Adding an endpoint to retrieve posts and comments is pretty straightforward, the interesting part is the realtime updates.
PieFed is using SSE in a limited way, to tell the frontend about new notifications and new private messages. The frontend makes a GET request to retrieve the content and then updates the UI. The backend code for this. The frontend code.
This would need to be extended to send events for all new content, not just notifications and PMs.
So we have the basic architecture already there and it wouldn't be much work to provide what you need. I have a lot of other priorities to deal with but if you engage with others in our matrix or zulip you might find someone wants to pick this up. Or make a codeberg issue.