Alternative to Luban for 3D Printing?

Luban is pretty bad at slicing for 3D printing, between invisibly disabling autofill and not printing top and bottom surfaces, Luban is fairly unusable. (I mean, it makes sense, right? If I change how to print the surface, then I obviously don’t want infills, and if I want high quality prints then I obviously don’t need top and bottom surfaces. So just disable all that stuff and give me empty disconnected shells that are too flimsy to use - exactly what I wanted).

Are there profiles for the Snapmaker 2 250 available for alternative slicers that actually work?

I only did minor testing, but Cura actually has Snapmaker profiles built in that work alright. You can also find A350 profiles for Prusaslicer here:

You should be fine loading the A350 profile and adjust the bed size under printer options to match the A250, since they’re technically the same machine, just different sizes. I use prusaslicer for my snapmaker slicing.

I use Cura. But Luban shouldn’t do that. It sounds like you enabled “Spiralize Outer Contour”. It’s designed to only print a continuous shell that doesn’t have infill or a top.

I’ve been pretty happy with the Prusa Slicer as a substitute.

The advantage Cura has is the option to use different sizes of nozzles and is extremely customisable.
I’ve used it for years on Ultimakers and wouldn’t change.
Try it out, its free and regularly updated.