I replaced my factory batteries with Victron Super Cycle batteries. They are rated for 300 cycles of 100% discharge, this allowed me to go with a smaller ah battery, shed some weight, gain some room in the battery compartment, and keep all my charging equipment. I sized my bank to routinely discharge to ~60%. I just couldn't justify the cost of lithium when lead acid would do the job for me at a fraction of the cost. I only get to camp about 30 days per year, so even if I fully cycled them I should still get 10 years of service.
https://www.victrone...-battery-EN.pdf
If cost is no issue for you, then lithium may be the way to go. You may need all new charging equipment as well. Personally I would not be comfortable with lithium "drop in replacement" batteries in a camper, these usually rely on an internal battery disconnect to prevent over charging. It would be better to have a charging system designed for lithium that wouldn't try to over charge.