Problem pushing from posit.cloud RStudio project to github repo that I own (repost)

I'm logged in to posit.cloud using my github account. I've created a project in posit.cloud from a public github repo that I own (GitHub - wjmatthaeus/CellsToEcosystems2025: stem-BGC code environment for summer training course.).

When I try to push changes to the main branch of that repo using my username and personal access token, i get the '403' error that seems to be a result of permissions.

I also noticed that my identity is not set up automatically in the RStudio instance, as it suggests should be the case here (Posit Cloud Documentation - Advanced Topics)

Farily new to all this, so maybe missing something obvious. Thanks in advance for your help.

problem is also posted here, in case it gets resolved
(Problem pushing from posit.cloud RStudio project to github repo that I own)