Not exactly the plugin you envision, but Graze¹ does this for interaction (boost, favorite, follow, reply etc) with posts on any instance. I guess the redirect

Not exactly the plugin you envision, but Graze¹ does this for interaction (boost, favorite, follow, reply etc) with posts on any instance. I guess the redirect and re-open on your own instance would be a feature for graze? IDK. ¹ https://addons.mozilla.org/en-US/firefox/addon/graze/ https://addons.mozilla.org/en-US/firefox/addon/graze/