You can definitely get a new crystal installed. $35 at my shop.
The magnifier is probably on with a UV-setting cement. I'm unaware of a
solvent for the stuff.

We used to remove sapphire bonded to glass with heat. Set the crystal on a hot
plate and slowly increase the temperature while checking the bonding. If the
crystal is sealed to the watch works, you probably don't want to do this.

Earle Rich
Mont Vernon, NH