As mentioned around the 300€ mark somewhere. So Neptune 4 Pro may be an option.

That’s one option and the one I was also thinking about. But it is triple the price for a few of the budget options.

That’s the software/firmware side of it but the closeness also applies to all the hardware. If something is broken you can’t get it from another supplier other than Bambu. And even that you have to think about “rooting” your printer is enough to never touch this Eco system. Keep 3D printing open!