facow [he/him, any]

Take a look at the docker-compose example in your link

volumes:

 - /media/<your folder on host machine>:/<location you want to mount to inside docker container>

Is Firefox installed as a snap package on PopOS? That could be it if that’s your only snap package. I’d recommend installing a Firefox fork that’s a regular deb package (Libre Wolf probably?) and seeing if that changes anything

Lmao isn’t Mint based on Ubuntu also? If you’re going to suggest switching distros entirely for slow loading on a single app might as well choose one that’s not derivative