I get why there are people that don’t like how some installers do this, but this trope is really turning into the “but I don’t even own a TV” of OSS commentary.
Just use the Docker image if you don’t like it. Or get their appliance which actually supports ongoing development.
Every plugin that is in that store must have a custom_components folder.
Drop that into the bind-mounted volume holding HA's configuration.yaml and restart. HA will pick it up automatically, and you'll be able to install it in Integrations and Devices.