there’s an ISO standard so there’s little debate any more. as i understand it, bambu only creates standard compliant 3mfs when you choose the non-default ‘generic 3mf’ option.
as i say, if bambu want to break the standard, then use a different extension for everything else.
See, you’re confusing industry standard with “supported by this archaic slicer nobody else uses”
It can’t open it because it hasn’t been updated to support the features all of the PS based slicers use
And bambu isn’t the one making the standard, like i said, BS is built upon PS, and if other slicers can’t be bothered to keep up with the times that sounds like a cura problem, install orca and use a decent slicer
And i should point out, that Prusa is indeed part of the 3MF consortium, just like ultimaker, so sounds like maybe ultimaker should take some tips