Version 12.0 introduced swipe to hide. This is not automatic but it is definitely better than nothing for your use case?
I actually prefer that over auto hide for lemmy, go back in a few minutes and you'll have more comments to read
Yes there's a way but it's slightly convoluted. You have to use the web interface or a different app like Jerboa to disable the "Show read posts" function in your profile settings. Then, in Wefwef, once you interact with a post, by upvoting or reading it, and then if you refresh the page, the post will be hidden.