"I didn’t want to get into the hassle of repartitioning everything that the boot loader works with both Linux & Windows."

Hmmh? I haven't done so in years, but configuring multi-boot used to be considerably easier than disk-less operation.

It is relatively easy to configure. Just install Linux after windows, and Linux will generally automatically setup a boot-selection screen for you. The installer should detect windows and even shrink the partitions for you.

You can install a prettier looking boot selection menu like rEFInd, but the default works just as well, and I think the mainstream distros all setup secure boot too. On my pc it was very easy, on my (8yr old) laptop I had to add some secure boot keys and the bios was very confusing, using terms that didn’t seem to match what they should have been.

My setup has worked almost entirely flawlessly and survived updates from both OSes. Only issue being “larger” windows feature updates putting windows back as the first OS in the list, but that happens maybe once or twice a year? And it’s a quick bios change to fix the order.

I've never had this experience dual-booting, neither with UEFI nor Grub. I've been using Linux for nearly 15 years, 13 of those dual booting. Dozens of systems from laptops to desktops. Windows would always purge the boot entries. I'd have to manually fix booting, constantly. This happened with Ubuntu, Arch Linux and recently NixOS and through all the Windows editions till 11. I had to install Windows for a lan party recently and lo and behold on the second day NixOS is gone from the boot list and unbootable. Nothing of value is lost when it gets purged, but it's a damn annoying tax to pay just to be able to play video games.

Luckily gaming now works well enough that the only reason to use Windows was gone. Well, apart from some online games played during lan parties.

The Debian installer is less than optimal for repartitioning.

The Linux NTFS resizing code also has a tendency to trigger data corruption. Not really Linux' fault, but it's a good reason to do partitioning from inside of Windows, which can be a pain already.

Another issue I've run into is Windows creating a very small (~300MiB) EFI partition that barely fits the Windows bootloader, let alone a Linux bootloader and kernel. You can resize and recreate the partition of course, but reconfiguring Windows to use a different boot partition is a special kind of hell I try to avoid.

>Not really Linux' fault

If Linux corrupts someone files, it is 100% Linux's fault and is absolutely unacceptable.

SecureBoot is a PITA.

For Debian and most other distros, secure boot isn't a problem. Installers are all using a signed, trusted-by-default bootloader.

There are some exceptions (some hardware from Microsoft doesn't trust the third party certificate used, for instance, and Red Hat Enterprise has their own root of trust if you opt into that), but they're very rarely ever an issue.