I'm facing the same; time to change the batteries. After looking at the options, I intend to stick with good old lead-acid (open) wet cells. I'd love to go lithium, but even though the prices have come down, they still don't make sense for my needs. And making this switch also means changing out large parts
of my charging
systems ... the cost goes waaaay up.
As far as AGM, to me they only make sense in specific circumstances such as laying them on odd angles, and/or being highly inaccessible.
Closed (no maintenance) wet cells are what I have now*. They'd done fine for me, but I wouldn't choose them again. I like being able to check, and top up, electrolyte levels.
* I didn't intend to buy this type... it just sorta happened