[throwaway365]

Extension support from the Microsoft Store has gotten to a point on Windows 11 where realistically only WEBM needs to be turned on for Icaros (And the occasional bad AV1 Extension update).
With that said, ProRes isn't included with the MOV support that Windows has. Is it realistically feasible to do codec specific Icaros generation until such a day that it Microsoft gets lucky?

[Xanashi]

Extension support from the Microsoft Store has gotten to a point on Windows 11 where realistically only WEBM needs to be turned on for Icaros (And the occasional bad AV1 Extension update).
With that said, ProRes isn't included with the MOV support that Windows has. Is it realistically feasible to do codec specific Icaros generation until such a day that it Microsoft gets lucky?

A feature like this is a bit too niche for me to spend the necessary time on. 
So I'm afraid, you will have to choose to use either MS or Icaros for MOV. 

You could as an alternative just rename all the files you only want Icaros to thumbnail to another extension,
like MP4 (same as MOV internally), or even a made up extension for that matter. 
Then add that filetype to Icaros' thumbnail filetypes list.