Qidi.
I've owned two and they've been very nearly completely turn-key (the OG X-Plus) and absolutely completely turn-key (my current X-Max 3). Their bigger machines are fully enclosed and have active chamber heaters to manage pain in the ass materials like ABS and ASA, and even polycarbonate.
They have their "own" slicer but it's just a mildly breathed upon fork of Prusaslicer with built in presents and which has all the plugins for remotely administering their machines already included. You can use stock Prusaslicer, Cura, or Orca with them if you prefer. The boards just run Klipper. You have terminal access, and you can hack the machine however you want if that's your jam.
Their upcoming gen 4 machines promise compatibility with an AMS-like "Qidi box" filament exchanger system, although the details of that remain unspecified at the moment. If you want multimaterial now they have a true dual extruder model also.
As of yet, there's no lockdown, no cloud bullshit (to be fair they do now have some kind of cloud bullshit platform available, but it's entirely optional and I've never touched it or even bothered to look at it), nothing proprietary, and so far there have been no rug-pulls on any of the above.