Windows is messing with that. A feature of modern UEFI boot, that OS-s can change boot order. This can be useful, after OS installation you don’t have to manually change back boot order from the usb to the internal drive. The problem is usually windows like to reset this to itself…
Arch wiki has an article about this, try to set this options in your BIOS: https://wiki.archlinux.org/title/Unified_Extensible_Firmware_Interface#Windows_changes_boot_order
I guess with the bios update some settings were reset to default, that’s why the behavior changed. Maybe reset your bios settings, and try to set up everything again from scratch, some old settings may be still active from the old firmware, etc.
Those are update services. Upgrading your os is a basic security measure nowadays. You recommend to sacrifice some security because of a minor inconvinience. It’s alright if you can live with that tradeoff, but please don’t recommend it on the internet. Windows assumes a user is not knowledgeable enough about this topic, so it’s enabled for them.
Other hint, because it seems you are also not very knowledgeable about this topic, usually you can disable these things with group policies if you really want to, so you don’t have to run it after each boot. Or you can also set up a scheduled task or create a service with nssm.