Windows, and some Linux systems can be installed on EFI systems with
Secure Boot. If that has been deployed, there will be matching records in your hardware's EFI/BIOS boot menu.
While I don't use Linux, I have installed it once or twice, and I recall installing Ubuntu with Secure Boot. It adding a boot menu record called "Linux" which I needed to delete before I could install and boot anything else from that drive.
--- Just to set reasonable expectations ---
Test 1: booting to see if a GENERIC kernel resolves the USB hub issue. Odds of success: low, but not impossible. My guess - 5% odds of success.
Test 2: booting to see if the internal drive can be used for an EFI boot of OpenBSD. My guesses - 95% odds of success if Test 1 was successful, 5% odds of success if Test 1 failed. This means having Test 1 fail and Test 2 succeed: 0.25% overall odds of success.