As far as i am aware any of my information i can provide wont help, it simple is an overlook bug or error purely on steam's end
using windows 10 currently
Essentially when you go to recordings and screenshots, Select... button and select one thing and try to export it, it will do as it should and ask what framerate, quality, encoding system etc but if you try to select muitiple clips it'll bypass this loading screen. the problem im facing is i have to use specifically h.264 and NOT hevc because my computer just refuses to show the actual video on it etc, thats not the important part, the important part is that when having muitiple things selected i cant switch the codec and theres nowhere ive seen where i can change the default meaning right now i have to manually export over 300 clips individually instead of all at once which i really dont want to do. if someone has a miracle cure of some obscure settings path to make what i want to do possible that would be amazing but as far as im aware this is just not possible unless i want to commit serious time into this