I don’t understand why you couldn’t use a higher amperage battery.
It’s no different than plugging a toaster into a 20 amp electrical outlet. Even though you can draw more current before the breaker blows, it doesn’t make the toast.. well.. toast any faster. The voltage is still ~120 VAC, it simply has more current available.
If it fits properly and is the same amperage or more, and is maint. free, you should be fine.
I have a higher capacity battery in my car than stock. It helps my electrical system. Higher amperage battery = easier starts in slightly discharged state. That’s what you’re looking for.