Good answer - as I suspected, your set-up, equipment and expertise is very good.
Myself, I achieve pretty good results with considerably less, got a choice of my old Samsumg Pro 815 or a Canon EOS 30D - both already almost 20 years old. I take pics outside with a tripod on an overcast day when the lighting is quite even from all directions (at my studio, outside, concrete all around). But then, my work is not all that large. The quality of what Horst Kaiser achieved on the few pieces I had him scan is quite a bit better of course when you get into oversize reproductions. The ones I took myself so far worked out not too bad, on same size as the original. I have yet to try enhancing my photos with the use of AI on Clipdrop Upscaler - but anything over 2x you have to pay for. I am notoriously known to be a cheapskate, lol. Otherwise I would invest in a proper Photoshop, instead of the old CS2 I got for free.