Yes 100% this is the problem. You can even add a redirect to Grub / systemd-boot to load the Windows bootloader from the other drive example for systemd-boot.

Does not work with bitlocker though without diving into very advanced settings to control which events are considered insecure so the tpm releases the keys.

It should work according to my research, though I do recommend trying Linux native alternatives as well. I personally went with Strawberry for now and it is similar enough for me.

I also dual boot on a laptop and a lot of games work well, especially via steam. I do have more problems with my GoG library and I had massive troubles to get Anno installed via Uplay. I’ve also noticed there are a lot of native native Linux ports coming out for some older games as well.

Just one piece of warning for dual booting, if the EFI portion for Linux and Windows is on the same drive Windows could decide to nuke the Linux bootloader with any update…

It’s not too difficult to create a redirect to the windows bootloader in Grub or similar, which is the solution I went with in the end.