Russia doesn't rely on GPS they have their own GLONASS system and the Chinese BeiDou system.
AFAIK there is a lack of satnav gear in general among their troops thus lots of units are getting lost (and subsequently ambushed/destroyed) after initial contacts/ambushes cause forces to disperse/change route and get lost.
Perhaps the Ukrainians did the old - change the road signs to loop around in a circle trick..
As I said before GPS for military is one more risk. Most would use it with the understand it could have been compromised. Most active munitions use ground mapping radar, however if that's out of date then you have issues. I think GPS arty shells are about the only thing that don't have a backup.