I had to go re-check my settings and saw that a lot of my “mark posts as read” options were unticked

For me there doesn’t seem to be an icon anymore, but instead the titles get a little bit darker. I also don’t have a button that lets me hide read posts either, but it might be because a setting got reset

It also seems like the devs introduced a bunch of regressions with the latest big update and have been quietly adding back in features. Things like instance/content filters, multiple accounts, and read settings were quietly added back in