The reason I mentioned I wanted to be able to swap out my AGM in the system instead of 'hard installing it' in is because I used it for 4 years on my offroad camping trailer. It still tests well, so I figured I'd run it for another year, maybe 2 before retiring it.
Lithium is good. I have one in my adventure bike - it holds a charge crazy well, starts faster, and is much lighter. Since I don't use the bike in freezing temps, I don't need to worry about trying to push a charge into it under freezing temps. My truck however, is in freezing temps so if I go Lithium, I know I can draw it down when it's freezing, but I can't push a charge into it without hurting it. The 'cold weather' lithiums have a BMS that senses temp and it will shunt the input power into a warming circuit until it reaches the minimum battery temp, then switch over to accepting charge. This delays the recharge of the battery, but protects it.
When I am travelling in the winter, I am not using much, if any cooler power. But I am using more lighting since it gets dark earlier. I could have little solar input due to cloud/rain, then if only driving an hour from place to place, all the alternator battery power would go into warming the Aux battery but not be long enough to actually recharge it. I don't think it is a huge issue because lights and cell etc. don't take much power compared to the fridge cooler.
The Bluetti looks great. The long charge time plugged into the truck is a consideration. The solar charge time is always an idealized situation. Maybe if you live in an area with reliable sun, closer to reality. Often reality is about half. Check to see if it can be charged in freezing temsps if that is part of your needs. I made a conscious decision to go with no AC --- all DC in my system. No conversion loss. If I need to plug something small in, I can use the trucks AC outlet. I do have a 2000W inverter I can bring and easily hook up, but that's more of an emergency use case run my fridge or freeze in the house in a power outtage.
Hope this helps.
