Voltage drop over long electrical runs sucks ... but you can't beat physics.

Here is a simple calculator where you can fiddle with the parameters and determine some of your cost/benefit tradeoffs.


Voltage Drop Calculator


Further, some equipment is very sensitive to operating at a voltage significantly below its design voltage. Other equipment can tolerate being out of spec.

(I do not know the tolerance of your pump type. I don't believe we have a true water well expert on the forum?)