minis" are a physical object ¬ something that can be imported
"Digital miniature models" might as well say .STL files(from WizKids), but that too would be another VTT user/operator (the DM) focused feature that doesn't fit with the exclusive player focus we have seen for this VTT.
Minis are 3d objects, thus 3d objects can be properly 3d scanned, and with some work converted to STL files.
There are also a TON of 3rd parties, kickstarters, patreons and STL sites that provide high quality STLs.
Now, getting those STLs from something to print to something to use in a 3D VTT might take some work, quite a bit of work actually. How much you spend on it, will translate to the quality. And then we also have an unpainted 3D model... You need to 'paint' it digitally (or import it in color via an expensive 3D scanner)...
This explains how to convert an STL to a 3D file useable in the Foundry VTT 3D module...
Why am I explaining this? Because you can do all this yourself for use in your own game, you just can't share it. So just getting a small range of STLs (or 3D scanned minis) into a 3D VTT is going to take oodles of time. Especially because the average DM/player isn't all that familiar with STLs and Blender...
As you see, the quality isn't that great, especially not compared to what you see from BG3... You need to buy the original files, spend time converting/painting it. How much is your time worth? At what point do you go: "Here have my money!" for a bunch of official HQ 3D files for your D&D 3D VTT?
And you can say: "We'll just reuse mini X for mini Y! It'll be fine!". Then why the heck are you playing in a 3D VTT? Just go 2D, you can make tokens easily from just the art of the monster, heck there are HUGE 2D token packs out there. Official ones for Pathfinder, etc.