Upgrading 2014 Mac Mini to Monterey from Yosemite Apple ID issue

I'm having trouble logging in in order to update the Apple 2014 Mac Mini. I had to do a recovery for this Mac Mini and created a user without logging in via AppleID. It's currently on Yosemite. I created an Apple ID account which I clearly can log in through the web. However, when I click the prompt to update to Monterey, it prompts for me to sign in using my AppleID. When I input the AppleID and password, I seem to get a 2FA text to my phone, but the UI doesn't prompt for me to input the 2FA code. Instead, it just says the password is incorrect. If I type it a second time, I'll get a second 2FA code but still with the password is incorrect. If I type it a 3rd time, it will ask if I've forgotten the password.

Is this a problem because the OS predates 2FA enforcement on AppleID accounts? Is there any way I can update this? I read that creating a bootable install disk requires another machine with the same target install version... which doesn't help me if I only have just this one device.