That abrading is something you pay for having the convenience of a removable with no holes antenna. You can lessen how much abrasion you have, but you'll never eliminate it. It just a matter of particles in the air and there's no way to prevent them from getting on/under anything that's 'move-able'. And just for grins, cuz it isn't going to affect that mag-mount to any degree, almost all car waxes are conductive to some variable extent. You might keep that in mind when waxing around insulators.
Any 1/2 wave antenna will have 'gain' over a 1/4 wave antenna, and any 5/8 wave antenna will have some 'gain' over a 1/2 wave antenna. If your present antenna is working on that HT
it will work to the same degree with any other radio (if the connectors are compatible naturally). How much difference would there be between any of those sizes/brands? Beats me, at least some. No idea if the difference in cost or convenience would be worth the cost, probably, maybe. A multi-element, automatically rotating beam would be even better! But they are a little harder to 'live with' and put on a car, sort of.
I think I'd give your present antenna a shot first, then decide. You also have to keep in mind that 2 meters (any VHF/UHF
band) has limitations, don't expect to hear 'B.F. Egypt' on any antenna. Maybe, but not very likely, sort of.
It's fun. Find out what you can do, then try everything at least once! (Till the 'significant other' puts 'The Foot' down...)