I've been researching the heck out of batteries. If designing a system from scratch, Lithium Iron Phosphate seems to win. But, you are dealing with the complication of a BMS (battery management system), built into the battery. Basically, a "smart" battery.
Lead acid, AGM, or GEL, or dumb batteries, just lack the capacity, or longevity of the lithium.
Firefly batteries, an AGM carbon foam, batteries, you can discharge down to nothing, and won't damage them, and have cycles up to 3000. Basically they should last you 10 years, if you are hard on them. If you are easy on them, like most of us during non SHTF, 20 years?