What's A Good Brand Scope With Polarizer For Viewing Coins

Have you tried just using a polarizing filter or sheet of polarized glass between the coin and the scope?

99% of "glare" is actually just direct reflection, and as @ijn1944 says, can be improved with diffusion. Polarizers in the "normal" sense won't work in this case anyway. The light reflected from the metal surface does not become polarized, no matter what the angle, so you won't get a benefit from using a single polarizer.

Only way polarizers can help is to use a polarizer on the light at the source, effectively polarizing it. If you shine this "pre-polarized" light onto the coin, the reflection from the metal surface will still be polarized, and you can use a second polarizer between the coin and lens to reduce the "glare". IIRC the pre-polarization must be done with a linear polarizer filter, and the reflected polarization done with a circular polarizer filter, but you should verify this.

All that said, photos I've seen taken with polarizers look very unnatural, so I'd still stick with the earlier recommendation to simply diffuse the light more.

Another possible option is to reduce exposure so that the reflected light does not cause over-exposure. This will allow you to make adjustments to the image, but it's likely that reducing exposure enough to not over-expose the reflections will cause the shadows to be under-exposed, so you end up causing another problem.