Does Nextcloud offer spreadsheets that can be edited on the server etc ? What would I use for that and how would I install it on my nextcloud?
See here: https://nextcloud.com/de/blog/how-to-install-nextcloud-office/
The easiest way to make it work is to use the Built-in Code Sever.
I just installed nextcloud office and then installed the Collabora Online - Built-in CODE Serv now my server is not responding after the install of the : Collabora Online - Built-in CODE Serv any ideas? does the install take over 15 mins?
No it usually doesn’t take that long.
Hmm not sure then… How much RAM does your server have?
Maybe you can reboot your server an try it again. There may also be an error message in the logs.
If you can’t get it working, I would suggest you open a new thread with all the necessary details about your setup. Please use the support template and provide as much information as possible.
It seems now that the server is running very slow. The server has a TON of memory. 256 GB so not a memory shortage there 
Yes, that is definitely more than enough. 
Unfortunately I don’t know what the problem is… Maybe a missing dependency like glibc GitHub - CollaboraOnline/richdocumentscode: Built-in CODE Server app
Not sure. It’s taking like 10 min to load the admin page after the install of that server plugin : Collabora Online. Also after that I can not get into my server via the command line or SSH so it has changed creds and everything sadly. Anyone else experiencing this?
The logon screen for the Terminal Looks different and seems to be RE-loading after so many mins over and over again. But no errors on the log on screen just wont let me use the creds I have been using for well… forever.
I found this, although it’s specifically related to the Nextcloud Snap.
There are also various threads in the forums, which are describing similar issues, maybe you could search for them…
https://help.nextcloud.com/search?q=richdocuments+code+slow+server
https://www.google.com/search?q=richdocuments+code+slows+down+server+help.nextcloud+GitHub
Another option would be to use the Docker container instead of the integrated app… CODE Docker image — SDK https://sdk.collaboraonline.com/ documentation
