I loved how slide for reddit solved that. You could set it to mark posts as read on scrolling them of screen and you’d have a floating button to hide read posts. So you could easily check for new comments or find new posts.

That depends. I think a one user instance as jumping point to the fediverse won’t be too much hassle.

You could host on Oracle free tier. I use an ARM free instance, which is plenty for me. And you can always scale or move somewhere else if you’d have many more users.