I have various MiniPcs with Windows 11, they work well.
I also have eg: HP Mini PC’s like @BigR with Windows 11 Pro and they work great.
I also have Mac Mini’s M2 Pro with OS26 & Win 11 Pro in (Parallels) and that works fine too.
I’m actually basing this on things that have already happened. Requiring an online account and corrupting other file system partitions is insane.
If Windows 11 install is corrupting other file system partitions on your main PC when dual booting, then you could eg: pickup another cheap standalone refurbished Win 11 Mini pc or refurbished Mac Mini computer to run it on.
I’ve done that with many friends where they eg: couldn’t run Windows 11 on old hardware.
As for myself, I had already noted that I still use eM Client and I’m running it with the help of Wine and Bottles which has been working fine thus far. But this isn’t something that the average person should have to do/think about and ideally in the future we’d see them visit their Flatpak GUI of choice and download eM Client from there.
I’ve no idea about Flatpack, but see the below post from @Michal_Burger for possible eM Client Linux options in the future on Wine or Native.