Thank you for your reply.
So I followed your instructions, disabled all the extensions. But YouTube still wasn’t allowing me to sign-in. Then I did YouTube.com > Lock > Site Settings > Clear data. Still didn’t allow me to login.
I then decided to sign out of all my YouTube/ Google accounts. And that worked!
The problem was that one of my other accounts was set as the default Google account. So I re-signed into my primary account and everything works now.
I watched a video that said to sign out of all your accounts and then re-sign in with your main account to make that your default account.
Now I’m remembering, when I was starting a new YouTube channel a year ago, I was experimenting with different names. And I uploaded the same video I made to two different accounts. I didn’t realize, but YouTube thought I was taking someone else’s video. But really it was my same video uploaded twice to different channels. Anyways, YouTube didn’t like that very much so they banned both of my new channels. Lol.
One of the accounts that was banned by YouTube was accidentally set as my default.
Hopefully this post can help others that deal with this in the future.
Thank you for helping me Brave team!!