based on your 2nd post, i'd follow inspector's advice & travel confirms it,,, you prevent water from entering your basement ONLY on the outside - from the inside, you can only manage it.
cost is a issue to address, of course, so compare,,, you might need to install an exterior sump & pump as just waterproofing the ext wall doesn't address the standing water which'd just find its way the the next weak point in the hull,,, new homes're only rqd to have a dampproofing coating ( usually an asphalt emulsion ), not waterproofing.
4 basic rules of wtr: 1, runs downhill; 2, seeks its own level; 3, rushes to fill a void ( eg, try making holes in bathtubs/pools/ponds ), & 4, winds up in bsmts.