The HomeAssistant "add-on" seems to be running things in a Docker container, see https://github.com/sunfounder/hom…man5/Dockerfile - which might be a simple (albeit heavy) way to run things. The Dockerfile needs minor tweaks to replace variables with content to be used on LE.
From a quick glance at https://github.com/sunfounder/pironman5 it's probably not that hard to make a simple Python script to poke the GPIO bits required to change fan speeds. Elsewhere in this forum you'll find an add-on for the Argon40 case which also comes with a fan and will be doing essentially the same things, though possibly with different GPIO pins being toggled.
Sunfounder seem to be maintaining the integrations for other OS, so might be worth asking them to look at LE too.