I can't add a phone number to my microsoft account on microsoft rewards.

it still dosent work and eventually the page just tells you to stop

It is best to simply give up. Microsoft doesn't give a rat's ****. I have tried in vain for months. I've tried everything. If MS says no, it's not going to happen.

I think I tried signing into Microsoft using the phone number as the "username" instead of my email address and came to the realization trying to do a security reset or something like that. Does that make any sense?

I finally solved this issue for myself so I'm just providing what worked in case it helps anyone else:

The problem was that I had my phone number set as a profile alias on an old Hotmail account I didn't use anymore. Once I was able to regain access to that account, I removed the phone number and was able to successfully add it to my current @outlook.com account that I use.

What's crazy is that I had many contacts with Microsoft support about this and no one could figure it out/help. I am kindly requesting Microsoft send me $100k for my consulting fee. Thank you.

I think or plan on buying a Playstation next time. I have always enjoyed that console many years ago, and Microsoft has just got to the bottom of the barrel with their product for games and rewards. They just aren't worth any hassle anymore.