How do I bypass the padlock password when reinstalling MacOS on a MacBook Pro?

The password for a Firmware Lock can be anything. It is not tied any macOS user account. Of course a user could have made the firmware lock password identical to one used with a macOS admin user account, but two passwords authenticate against different parts of the system.

If you are the original owner and you have the original proof of purchase, then you can have Apple or an Apple Authorized Service Provider remove the firmware lock, but you must provide acceptable proof of purchase & personal ID to match.

I have also seen a firmware lock occur in relation to FindMy as well which can sometimes be cleared with a PRAM Reset once the FindMy activation lock was removed (the firmware lock is sometimes a side effect of removing FindMy activation lock).

If you cannot provide the proper password and cannot provide proper acceptable proof of purchase, then there is nothing else you can do with this laptop.

Set a firmware password on your Mac - Apple Support

the login password of an Admin user. if yours was the first or only login created on that computer, it is looking for your login password. [NOT your Apple-ID password]

MacOS is inherently a multiple-User system. When you choose to create only once user, you may get lulled into thinking the entire machine is all yours. But it does not operate any differently with only one user.

My apologies.

HWTech is completely correct. When you said a padlock, I was visualizing an ordinary authentication padlock. On re-reading, I can now see you meant firmware lock, and my advice was not applicable for that.