Windows ext4 compatibility is awful. I have my steam library on an ext4 partition, and occasionally boot to windows for specific games that don’t work in linux. I tried mounting my ext4 partition using WSL (which worked fine), adding the steam lib folder to steam (worked fine), but all the games wanted to be verified before being run, and then i finally started one and got a BSOD. I thought maybe steam might complain that some files were wrong, but I didn’t expect that lol. But at least steam tried, Epic launcher just flat out refused.
I haven’t tried btrfs in windows, I see WinBtrfs exists, I wonder how well it works.