trying to figure out what i have to do to my nextcloudpi server to allow for Joplin sync. Can anyone point me in the right direction? All I find is very old articles on it that don't seem to apply.
Note that Joplin sync is connecting directly to your Nextcloud server.
So...
If you also have the Nextcloud Desktop client installed on your computer (it is not needed for Joplin sync) go to the "selective sync" settings in the Nextcloud client. If the Nextcloud client is set to sync everything, exclude (untick) the "joplin" folder you use for sync. If you do not do this the Nextcloud client will unnecessarily make a copy of all your sync data back onto your computer and possibly bombard you with lots of notifications telling you about it.
There is Joplin Server software available that can be run using Docker. It is a self-hosted version of Joplin Cloud. It is something you could install on a system to use instead of Nextcloud, it is not run using Nextcloud. Both Joplin Server and Nextcloud can be used as a way of syncing files between Joplin clients. However Joplin Server is designed to work only with Joplin clients, whilst Nextcloud is a more general purpose online storage server.
I suggesting using Joplin Server if you can. If you're running Nextcloudpi you have the know how and hardware to run Joplin Server. I like being able to share notes as webpages, it's a good and easy way to share information with friends and family.