tested on t14 gen 3 with bios n3met27w

update thinkpad t14 bios

turn thinkpad on and press f1 to enter setup.

select security > secure boot, set secure boot to disabled.

select security > i/o port access, set bluetooth and fingerprint reader to disabled. these devices are not supported by openbsd. disable other devices you don't use.

select config > sleep state, set windows and linux.

press f10 to save changes and reboot.