Everything Ive ever read about AGMs is they are NOT the best choice for regularly deep discharging- discharge should be more like down to 60%.
Holding charge on battery and discharge percentage in volts, regardless of type, is pretty much the same .
GELs charge at a lot less rate than Flooded or AGM batteries so a GEL setting shouldn't be used for AGM or flooded wet cell.
Not knowing what "sealed" is on your charger, though instruction/manual may show a charge rate chart which would help identify, flooded would be my choice unless 'sealed' closer (higher bulk & less float than gel)
'Depends' is a shrug and dunno-though in fairness no pat answer.
another good article
https://www.westmarine.com/