I can assume you enjoy cycling, I can also assume you enjoy cycling with fellow club members, and since some of those have gone over to E-bikes, not sure why you are debating this. Certainly, get an E-bike, it will take some of the strain off your knees and thus reduce pain, plus the constant pedaling motion is actually important to keep your knee pain down, if you stop riding the pain will get worse because you're not keeping the fluid in the knee healthy.
By the way, E-bikes do have a hidden cost that bike shops don't talk about, and that is the cost of a replacement battery. Replacement batteries cost around $700, and they last between 5 to 7 years, so keep that in your budget.
Not sure if you have been down to your local health store, but there might be some supplements you can take to calm down some of the pain. Also, stay away from foods that are inflammatory, you can research that on the internet, and stay away from sugar, sugar drinks, processed food with sugar, candy, etc.