I'm currently using Nextcloud/CODE after using OnlyOffice and it feels more stable but way slower to render a text.
It works, but at the moment of scrolling the pages the browser shows white empty spots with a clear lag at rendering the text. Here there's a video I took that shows what I mean.
I don't think there's a system memory problem:
This is my CPU usage:
Any help, I would be really appreciated.
This seems to be a highly app specific issue. As far as I remeber, code renders document tiles which is what appears to be rather slow for you. As those are possibly only very short amounts of time where cpu spikes, it may not show up, but might be worth looking at
htopvia SSH during scrolling and see if the CPU is the problem. Otherwise you probably have to seek help with the upstream project I guess.