@nikolal @syntax
The thing is, Nextcloud has a built in OnlyOffice server (by default) starting from NC 19 I think. Previously you needed a separate server for it.
NC 20 has even more features (I did not yet upgrade).
With such rapid growth, I would not count on RPi 4 to handle NC now, or maybe not in near future. I may be wrong though, I never owned an RPi myself.