Disclosure: I'm CTO at Fleet. One of the biggest challenges is the vendor lock-in that results from the way the MDM systems work (particularly on macOS). In typical MDM solutions you don't own the keys and can't manage migrations without direct interaction from every end user. We expect Broadcom to milk this friction while they can.
One of my fav things about this is that we're solving the "Linux MDM problem". As a person who likes to use Linux, it's exciting that, no matter how big the company gets, I can still use whatever OS I want at work (and still be "offboard-able", with everyone passing their audits.)