Allow a custom path, where default, empty files templates are looked up. Those are in particular relevant for new.docx , new.xlsx etc.
This way we can provide our standard default templates to users.

I can think of the following:

Prio 1: Look up custom template path specified in OO document editor settings
Prio 2: Look up fixed custom template path in users documents folder, like a subfolder Onlyoffice-Templates
Prio 3: Lookup default templates folder

Higher prio would take precedence and upon lookup would use that one, ar fall back to the next prio.

That process would cater for so many use cases.
We could provide standards to users, could cover Windows users but also Ubuntu users.
Would be able on Ubuntu with Onlyoffice Snap to provide a new.docx with German (Switzerland) as locale and spell checking default, since German (Switzerland) is not available per default and was requested many years ago, but nothing happend.