Probably has to do with secure boot and your Linux installation didn't install a valid shim for uefi to boot it, thus it moves to the next entry which would be Windows.
I have observed that many laptops are hard-coded to boot windows whenever possible. Even with windows bootentry missing, firmware will skip Grub set to first priority and start windows. Only way to make them start Grub is to rename bootmgfw.efi to a different name.
Windows will not boot with this method. By renaming the file back to bootmgfw.efi windows will boot again but now linux won't boot. There is no clean solution, other than switch to different computer that doesn't have this issue. Because of issues like this I don't recommend dual booting. Installing only Windows or only Linux is more manageable for not-tech-savvy people.
Out of curiosity what's your use case for dual booting? I know it's a common choice for new Linux users and I did it too out of fear that I'd be missing something I need Windows for, but I've been completely Windows-free for a while and much happier for it. When I did have a Windows partition I never booted into it.
For games, Steam's Proton works pretty well for most games these days. You can check https://www.protondb.com/ to see if your game works well with Proton.
I've also had good experiences with Wine for productivity software. Similarly, you can check https://appdb.winehq.org/ to see how well your program runs on Wine.
Worst case scenario, if you have a decent enough PC, you can always run a Windows VM and that should run more or less anything.
And all of these avoid any trouble with Windows eating your grub install etc
i have a weak laptop, with windows on the m.2 ssd and i'm trying to boot garuda from an external sata2 hdd, connected with an usb adapter. I have many important files on windows, and c# is mostly impossible on linux. I can't run a vm, because i don't know how to set up quemu, and my laptop is waay to weak for that
windows 11 pro. No matter what, all windows overwrites grub whatever i do. The only option i have left is to buy a pc and swap the ssds, by physically removing one of them before boot. no other way to dualboot