Hi Chris,
Thank you for sharing your question. I get how annoying it is when you change your password online but still can't log in on your computer. Restarting and waiting were smart moves; it's obvious you're trying to fix this the right way.
Based on my knowledge this usually happens when your computer hasn't updated with the new password info from your Microsoft account. If your computer is offline or using old, saved info, it might still be trying to check the old password or PIN.
Here’s what you can do to fix it.
First, check that your computer has internet access before logging in. If it doesn't, it can't check your new password with Microsoft.
If you're using a PIN, click Sign-in options on the login screen and pick Password instead. Sometimes the PIN gets messed up and won't accept the new one.
If you still can't log in, try starting your computer with Safe Mode with Networking. This can skip some login issues and allow your system to update the password.
If nothing works, you might need to use Windows Recovery Environment to reset your password or get into your account through another admin account if you have one.
May I also ask, are you logging in with a Microsoft account or a local account? Also, can you get into another account on your computer that has admin options?
I hope this answer is helpful, if you have any questions, feel free to reply.
Best Regards,
Noel