Not necessarily a button, just came to mind first.
Noticed a moment ago after blocking a community I’m not interested in seeing, there was no quick and easy way to get to the top menu to refresh the feed. A button or pull down method to quickly return to the top of a feed, or just show the top bar quickly would be nice!
Small scroll up, at max half a post, usually pulls the menu down for me to see the 3 dots and be able to refresh or goto top