If you run NCP on a raspberry pi, it can work really great for a few users. It’s not the setup for a huge user base, and also there are a lot of pitfalls where things can go wrong. Already with 32bit OS, it is a bit more tricky (there were and there are probably still a few bugs regarding large file sizes). But also on the hardware side, you can do things wrong, e.g. if you get too much power from USB, the device gets very unstable and crashes. In such cases, all the updates won’t help.
Nextcloud Pi already did a great job in simplifying the whole installation process and optimizing a lot of the settings to fit the Raspberry Pi.
There is a section with documentation about NextcloudPi:
e.g. if the performance of the Raspberry Pi is not enough: What modern hardware do you recommend for NextcloudPi?
or boot from external disk instead of SD card:
Raspberry PI 4 – Booting from USB Device (no microSD)
And if you don’t like the NextcloudPi concept, you can install Nextcloud directly on a Linux yourself.
For issues here, we ask to fill out templates in order to have a bit more information about the problems and the used setups to be able to help faster and give more precise answers.