RaspberryPi becoming unresponsive at random intervals

Issue Description: I have been having this issue with my raspberry pi running dietPi where it seems to lock up and I cannot SSH / access any of the services on it. The interesting part is that the interface seems to be up and I can still ping it on the local network but shows no video output. usually I get about 3-6 days before the issue appears again.

I am not really sure where to start to diagnose this issue. Any help would be appreciated!

Things Tried:

Reduced operating temp by getting a fan. I want to say this improved the length in between this issue appearing but don't really have any hard evidence.

uninstalled unused services

Limited active torrents in QbitTorrent

EDIT: Small thing to mention is that the CPU load is usually really high - like not uncommon for the load to be between 8-10 but I have seen it as high as 24.

Temporary fix:

Power cycle - everything comes up again in less than a minute.

Raspberry Pi 3B v2

OS: DietPi

Services:

Lidarr

Radarr

Sonarr

Prowlarr

Qbittorrent

Mullvad VPN - WireGaurd

SSH