@mattes3 the front-end and the admin are intentionally disconnected for security. With most setups there’s no way for the site to know if you’re logged into the admin area which precludes making a conditional button.
The /edit url redirect is the best way to jump from a post to the edit screen. If it’s something you do a lot you could always add a script to your theme/code injection to implement a hidden shortcut so that if you pressed Cmd+E for example it loads window.location + 'edit'