before I ever install their unnecessary and untrustworthy data-miner
You’re about [current year minus year you installed Win10] years too late for that. That said, if you intend to come over to Linux, it’s probably best to set time-bounded goals for yourself instead of vaguely putting it off until MS does something that crosses some poorly defined line, else you risk having to chaotically abandon ship at the last minute and making the transition much harder.
There isn’t a meaningful difference; gachas are just a subset of lootboxes, and anybody claiming otherwise is a player lying to themselves or is a game publisher defending themselves from these predatory practices.