Not sure what works best in your case. I’m a Debian cat myself but I have been considering openbsd as a future option.

I’d try each application one by one. Maybe write a script to monitor load and stop the program if it goes past your desired threshold and notify you.

It could also be a setting in some app like photoprism or immich … I think one of them uses tensorflow to classify images. That would increase the load if thats running in the background.

Maybe try them with an empty directory so there is no data to process and see if you encounter the error. Then add some data and see how the load is.