At the moment the "Online-Update" is listed in the preferences under LibreOffice --> Online-Update. It is better listed under Internet --> Online-Update.
For me it doesn't really matter, but because Update is a more general Libreoffice topic and the section Internet is more regarding the technical internet connections, I would propose to keep it. But of course, because it speaks of update intervalls one could also argue that this is a technical thing which could be under INTERNET. But currently I would nevertheless still propose to keep it. But let's see what others think. Note to find it: Go in any LO component to TOOLS -> OPTIONS -> section LIBREOFFICE -> subsection ONLINE UPDATE
Let's ask the UX folks.
It is in the correct category since we are "updating" the LibreOffice installation, not configuring the Internet connection/proxy. Can't see that a move under the "Internet" panel would make add any value or make much sense.
Looks like a -3 for the idea (-1 from me). Rather we should consider to simplify it as an on/off feature. There is no good reason to change how frequently the check is done. But it _looks_ nice and user-friendly on the other hand. Closing this one as WFM.