I have tried removing the portal, readding it, resigning in to the portal, removing the layer, clearing the pro sharing cache, it is stuck. Closing and reopening the map. I feel the last thing to do would be to redownload?
Have you tried under other logins to your portal or your database? For whatever reason one of my many database logins doesn't like me to publish even after hours of Esri combing through the user properties.
Is this the only layer giving you problems?
Does your C drive have enough space to hold the temp files that are created when publishing?
If the C-drive does not have enough space for temp files, doesn't the ESRI software warn you about this so you know this is the issue?