That's not a real problem.
Even if you install a new bootloader, e g. a new GRUB, you will be able to select via efibootmgr which one should be used by default.
Garuda, of course. Not only because we like it, but because GRUB from non-btrfs systems will have problems probing Garuda. Not the other way round.
First is Garuda os which I have no problem but when windows update it takes times and restart several times and each time I have to select windows or it'll boot into Garuda.
This makes me sit whole time on screen while it updates.
Sorry but it's not clear to me what you mean with change priority.
Efibootmgr defines which bootload the boot process will launch. It will use the first in the list, and if not found will go to the second one and so on.
So, if you put Garuda as first, it will launch Garuda's GRUB. If you put Windows, it will launch Windows bootloader. If you install a new Linux distro and put it first, then it will launch that bootloader.
Then, if the launched bootloader is GRUB (or any other boot manager) it will allow to manually select which OS to start or will use a deafult.
This deafult can be changed.
But nothing is related to priority in my opinion.
To use efibootmgr, refer to many tutorials on the internet. E.g. (disregard the installation of course).
If the need to use Windows directly (without going through Garuda's GRUB) is sporadic, you don't want to use efibootmgr every time, but at boot time go to the BIOS (there is always a function key to do this) and choose there to use Windows for that time instead of Garuda (or rather Garuda's GRUB).
Sadly, given that Windows needs to reboot automatically to update, for that to work unattended it would need to have Windows bootloader as default in UEFI (or in GRUB, but that's somewhat pointless).
In both cases you'd have to manually choose Garuda when you want to boot it.
One thing that may work to make the process less tedious in case you want to use Garuda more often than Windows (I hope so LOL): if there's a Windows equivalent of efibootmgr, run that to set Windows default before updates, and similarly use efibootmgr to set Garuda back to default when you boot it.
Find the correct arguments and write a one line script to avoid having to repeat them.
You may run it on start automatically, after configuring sudoers to let you run it without typing the password again (do your own considerations about the safety of doing so).