I spent 30 years as a manufacturing engineer in electro/mechanical items. We had government contracts which required ZERO damage to wires we were installing. Nicked and broken strands would be rejected. The only way we were able to accomplish this was with thermal wire strippers. They have a heated element which allows separation of the insulation without sharp edges which damages the underlying conductor.
A commercial version can be very pricey, but I'm attaching a link for a stripper which should work good for occasional hobby usage. It's less than $100 and should last quite a while with only occasional usage:
Thermal Wire Stripper
