There is currently no way to adjust the authentication frequency current (may change in V1.0??)
However, you can create a jellyfin user that's only job is for Homarr integration (it doesn't need any permissions). This will at least make filtering the logs easier.
Homarr also only connects when the widget is open/being viewed. So if no one has a board with the JF integration open, it won't ping all the time.