Calcium sources *do* tend to increase the pH, but you can still add them in small quantities. Bonemeal is not a great source and is slow. Oystershell meal is great if you can find it. Ground limestone (not dolomite) is OK, but increases pH faster.

The best thing one can do for a soil that tends toward the high side of neutral is to regularly add organic matter, ideally finished compost. It will help with both pH and availablity of calcium. Lots of compost!

Placing amendments ”in the planting furrow” is not going to be effective; the must be incorporated into the the whole area.

I only grew them for a couple of years in a not-acid soil, and the first year production was poor and there was a lot of brown spots. By the second year of ammending the soil with loads of compost the production was good and spots were few.

Others hopefully will chime in with their experience growing potatoes in high pH situations.