I need to do this with my gaming computer yet. I run Linux on my other machines (and have for many years), but this one is Windows. I bought the computer in 2021, but it doesn't have the trusted computing module, so I can't upgrade it to Windows 11 even if I wanted to.
Last night I tried to add an SSD that I had from a laptop that died, figuring I'll put a fresh install of Linux on the second SSD and not touch the original drive. Unfortunately, the computer didn't want to boot off the original drive any more - even when I changed the boot priority to the original drive, I still got grub from the new drive. I had to disconnect the new SSD to get the computer to boot Windows on the original drive (I wasn't ready to do the Linux install and might need Windows in the mean time).
I know it's a temporary issue at worst, as the installer will likely pick up that Windows installation and make it an option in grub. But it was a setback I wasn't expecting. I figured I'd put in the drive and have it just idling there until I had time to run the Linux installation.