I've been looking every now and then over the past several days. I still haven't found anything. Will try the tar file, but I'd rather have a repo that can automatically update me whenever necessary.
I'm uncertain what you're looking for. The downloads of TeamViewer Host for Raspberry Pi are on the download page: https://www.teamviewer.com/en/download/linux/
If you already have TeamViewer Host (DEB/RPM) installed on your Pi, you can just update it like every other package, e.g.
apt install teamviewer-host