Even I had the same question in my mind. I wanted to monitor my NUC that’s running firewall. If the temperature goes above threshold value a smart switch May power on DC fan kept near the NuC to provide additional cooling
I’ve got another option you might consider - I wrote a daemon (called dunnart) to monitor my remote Linux boxes in HA via MQTT. It uses MQTT discovery to automatically integrate with HA, so it is pretty easy to setup - the most complicated part is setting up the config to connect to MQTT server.
It is a small standalone executable that is very flexible on what attributes it monitors and how often it sends updates. It can monitor cpu temperature and usage, memory usage, file system usage, network usage… but it will only monitor the attributes you select.
It doesn’t do GPU temps yet, as I typically run it on RPis where that isn’t an issue, but it would be pretty simple to add that option.