You absolutely can replace an AGM battery with a wet-cell battery. You just need to code for the change so it charges correctly (AGM and Lead-acid batteries require different amperage during charging). There is definitely benefits to running AGM batteries though.
I wrote this comprehensive guide on how to register/code a battery:
https://www.[spool]street.com/forums...-battery.1020/
Remove the brackets [] around spool.
It walks you through some of your other options.