(SOLVED)Triple booting windows & 2 distros; remove one distro, how to?

[Tolkem]

Hi everyone! Hope you're all having a nice life!

Due to work, I recently had to install Windows so was dual-booting, I installed another distro, so now it is Windows 7 + Debian stable + Debian testing. I didn't manually set any partitions, just let the installer do that for me. Thing is, now I might remove Buster from that equation since Bullseye is working fine and would be nice to regain that space. I have dual booted in the past and know how the process to remove Linux is, and think I know how to do it this time too but have some questions since it is a bit different from what I'm used to; I only did this in Legacy bios machines, this is UEFI I'm talking here now and not sure whether it's the same procedure. I did some research and found some blogs and post about that and this is what I think I have to do:
1. Boot to windows and remove the partition where stable is installed in.
2. Fix/restore windows bootloader?(or not? I think not, this will delete Linux from bootloader, but 1 Linux will still be there)
3. Boot to Linux run

sudo update-grub

?
4. ??
5. ??
Is this correct? Am I missing something here? I might just do it and see what happens anyways but would appreciate some advice.

 

[f33dm3bits]

No idea since I don't dual boot, just replying to wish you good luck with dual booting!

 

[Tolkem]

No idea since I don't dual boot, just replying to wish you good luck with dual booting!

Thanks... though a "do this, do that...don't do this, don't do that" would've been nicer

 

[Tolkem]

So, I removed Stable and was actually easier than I thought it'd be. The partition containing the distro one desires no longer to keep, should be deleted from Linux, not Windows. This is due to the fact that both Distros are being managed by grub, not windows bootloader. Here's how I did it, for anyone else who might be in the same situation:
1. Boot to the distro one want to keep and delete the partition. Make sure to back up important data first.
2. After deleting the partition run

sudo update-grub

3. Reboot. Hopefully, everything should be in place and Windows as well as Linux should be able to boot without issues.

 

[KGIII]

That's what I'd have done, mostly. I'd have nuked the partition in question and then updated grub, perhaps using grub-customizer to simply remove the entry.

Glad ya got it sorted.