How to get my cat to stop spaying my electronics!?

Try asking in the correct CATegory, this is dogs. Vets spay, after they've gotten their license, not cats.

Spaying/neutering of a pet does not make up for lack training........

Have you had a vet check a urine sample to make sure there's not a medical issue that could be a factor? If all is well physically, there's a variety of things to try. There's specialized litter like Dr Elseys Cat Attract (there's a money back guarantee, so worth a shot), pheromone products like Feliway that often stop or reduce urine marking, CBD hemp supplements (like Canna-pet) that can help relieve anxiety and reduce marking, and a wide variety of environmental enrichment and lifestyle changes that often help, including increased play and added cat furniture to create high perches where he'll feel more secure.

It sounds like he was neutered later on in life, which means that his hormones that tell him to mark his territory are still there, so he sprays to mark his territory.

If "he" is 'desexed,' why do you keep saying he is spaying stuff? He cats aren't spayed, anyway. On the other hand, if you're talking about SPRAYING, say so.

How to get a cat to stop peeing in and on your stuff.........? Yeah, get rid of him. Once they start, they don't stop.