The error you're getting with SSH isn't a problem with the pi, your local user is not root which means you cannot bind to any port <=1024, try listening on local port 8080 instead with -L 8080:localhost:80
I've deleted the old app and just put my current Lemmy app there, when Sync for lemmy is published I'll replace it again. This way I don't have to change a thing about my habit