I think Krita is a more viable competitor to Photoshop than Gimp at this point… It’s also great for pen tablet drawing and arguably superior in that category.
But yeah, video editors are lacking. Kden live is ok (and awesome for the price)
Audio editors are behind too. Audacity is pretty good for 2 track. Bitwig is a great multitrack alternative to Ableton… But Ardour isn’t developed enough for a pro studio and I’ve never seen one that uses Linux. Part of this is poor support for vst plugins developed for Windows, mostly due to their copy protection.