I assume you could open it up and reset bios by shorting a couple of pins or pulling the CMOS battery. Google the ThinkPad model number and "bios reset".

Note that if safeboot is enabled this could lock you out of the OS, but given that you were able to wipe the OS without accessing BIOS anyway, it makes me think it's not.

Do with that information what you will, good luck.

https://support.lenovo.com/au/en/solutions/ht036206-types-of-password-for-thinkpad

Reset forgotten supervisor password

If you forget your supervisor password, Lenovo cannot reset your password. You must take your computer to a Lenovo Service Provider to have the system board replaced.

It won't matter that much UNLESS a specific setting you might want is disabled such as virtualization.

Consider checking now if virtualization is enabled or disabled. If your BIOS settings are fairly permissive it isn't that big of a deal. But if they are restrictive it can make it a pain in the ass to work around.

IMO, Honestly, at this point you probably arent going to miss much.

Youve presumably booted from an external device and installed an OS. I assume the time amd date are right.

Only question really is are you using efi or mbr boot method. If efi, you are probably fine and future proofed unless you want secure boot (windows) you may face an issue then. Thats not to say you will, just you might.

Try this

bios-pw.org doesn't explicitly say it supports any Lenovo products, but I've had luck using them with Dell products before. No clue if this will work for you or if it's a generic article meant to suck you in and grab ad revenue.

You can either try to contact the seller and ask for the password or just erase the UEFI settings by shorting some jumper or something. There should be instructions how to do that for your specific model.

If it's not an issue, it's not an issue. If you need to change the settings at some point, you could look up if there is a way to reset the password. Or sometimes there are tools that let you change the EEPROM settings from linux, without needing to open the BIOS. Depends on the hardware.