Quite simply, is there anything to help the belts?
If a belt is wearing out, there’s generally a different problem. If you fix whatever that is, the belt wear problem should vanish. Do you have photos or more descriptions of the issue?
An aluminum pulley generally wears out at a similar rate to the belt itself in my experience.
I only have a 6s Eglide right now, but am building a powerful machine. I know big wheels help, due to large pulleys. And, I have a 16 countersprocket. But I have only ran my board dry, so I ask.
I don’t think belt wear is going to be an issue — at all — for you.
You should focus more on getting a high-quality battery and completely forget about belt wear and don’t design around that.