Advice before deleting and reinstalling NC (stopped working)

Apologies in advance if this isn’t the best category to ask.

I have been running a small NC instance on a Raspberry Pi 4 for a year or so as a cloud solution for personal pictures. I managed to get it up and running, secure an external LAN access via VPN and its been doing ok.

My issue is that I’ve always had to tinker the setup every few weeks for various problems and this time, I can’t seem to solve the problem on my own.

I would like to know if there is a more user friendly solution out there to facilitate maintenance. Like an installation procedure that would be more fitted to my aptitudes. Installing NC on a RPi was my first time using a Linux based OS (Raspbian Buster).

Any insight would be greatly appreciated.

Current setup is NC v.18.0.4 (won’t let me update)
Raspbian GNU/Linux 10

Here are screenshots of the administration overview, system overview and results of my RPi df -h and lsblk

Any help is much appreciated, thank you for your time!

Mugatu

Got a step further today, my data folder in Nextcloud just took 21GB of unknown weight as shown here Unknown space eater spotted - Album on Imgur

Any suggestion on potential solutions to free the space needed?