Hi Josh,
I tried to follow these instructions, but I couldn't find the manage-add on Link. My problem is a bit similar but also complicated and it's driving me nuts over the past few weeks. Briefly, In Dec 2020, I made a LearnArcGIS account, I also purchased ArcGIS pro through that account as well and started work on pro. A few months later, this account was as per policy disabled. Subsequently, I couldn't log in to pro either. I contacted support and they instructed me to make an Esri public account and given a token no. I told them I had already purchased pro and its license and didn't want to purchase another license again, as it would be money wasted.
I made a public account and fed in the token number. When I tried to open ArcGIS pro application, it gave an error message “ Your account couldn’t be used to authorize ArcGIS pro because it is an ArcGIS public account”. I contacted support again, they weren't able to help me, I was directed to this community page as a last resort.