A SaaS company enjoys full control of their cloud servers and licenses use of their proprietary webapp to you. A hardware company sell a physical product that you own and is not morally allowed to yank functionality later. As far as I'm concerned their cloud servers are part of their product and that's a hill I'm willing to die on. Anything short of that is a blatant bait and switch.
I'd be willing to settle for them offering fully refunded returns to all affected customers who want it. Failing that I'd expect the court system to award appropriate damages. This sort of scenario is literally what consumer protection laws were created for.
Edit: I (and many others) might be operating under a misunderstanding? It looks like all (?) the advertised functionality might be available (at least for now) locally via MQTT. But I'm not entirely clear on that. https://github.com/Doridian/OpenBambuAPI/blob/main/mqtt.md