It seems like I messed up cause I installed manjaro in UEFI mode so now my grub doesn’t see windows (which is as far as I understand using BIOS) and only boots to Manjaro (according to other forum posts here)
Although (it seems like) I figured out the problem I can’t find a way to boot into windows to uninstall Manjaro so it would be amazing if anyone could help me.
I have also tried to backup my full system with timeshift but for some reason i’m not able to resize my NTFS HDD and make another ext4 partition to back up in there.
Some details: I have dual boot Windows and Manjaro in my SSD and have a 1TB HDD; I have tried booting windows from my UEFI but nothing worked .
Sorry just in case if this question was answered, I really wasn’t able to find a solution so far
When I added HDDs with additional operating systems after installing Manjaro, the Grub didn’t have os-prober running by default (thus no new OSes were discoverd) but Grub Customizer ran the update and discovered all operating systems including Windows on all HDDs (and the result can be easily edited). I don’t know whether it solves the UEFI-BIOS issue though…