Let's dig into performance a bit. Your gen8 server i believe is using E5-26xx CPUs which is plenty of power for speedy performance in Nextcloud. You mentioned upgrading the CPUs and RAM so should be good to go.
- Ensure application files are stored on a SSD. I have seen significantly poor performance in Nextcloud when it's running fully from HDD storage.
- Data storage is fine to remap to HDD storage. If running with docker this is as easy as:
volumes: - /HDD_storage/nextcloud/data:/var/www/html
- Make sure to run Mariadb/MySQL for the database as opposed to SQLITE.
- Ensure REDIS is used and working. This will cache and speed up the UI.
With all of that working correctly, Nextcloud is very performant on my comparable Dell R720.
Edit, I see below you are on a microserver. I think all of the above still applies but I don't have any experience with that hardware. I would still expect it possible to perform well on that device.
No problem at all! I was reluctant to comment as it seemed that you weren't interested in pursuing Nextcloud any further, but went ahead with my comment because I initially had very poor performance when using the basic container running with SQLITE.
I will admit that I had sync issues with a notes program when putting the file on Nextcloud. Some apps just aren't compatible with that storage paradigm it would seem.
Thanks for the thoughtful replies and good luck on your search!