Sorry if i come across as a bit terse, but this is one of my pet hates, where people have been told 3d printers are able to create anything and are a magic solution to everyone's problems.
3D printers are not magic. Despite what the media would have you believe. I own two high res machines and produce minis using them to make a
master prototype for resin casting. High res machines use SLA which involves expensive resin, they are slow to print and expensive to run. You can buy a FDM machine for cheap, but its not suitable for miniatures. (large pointless blocks of plastic "art", yes - it can print those just fine if thats what you like)
Problem 2 is; to transfer a mini into digital format involves digital scanning. Which, again, is either expensive, or cheap and inaccurate. With scanners under £500 you will scan a mini and get a blobby balloon animal in your software. Or pay £15,000 for a high res medical scanner. Or pay a scanning company to scan for you at £120 per mini (breaching copyright laws, so most scanning companies wont do it)
So in conclusion, yes you can make HQ minis on a 3D printer... if you want to pay £120 to illegally scan a mini in high res, then buy a £8,000 printer which is suitable for printing miniatures, and then create one mini per 5 hours of operating time and pay £10 in materials and consumables doing so, and then still have to clean up the support structure which leaves a mess if you dont know how to prepare parts well.
Or you could not do all that, and just cast it in silicone and resin for £2 a model