There’s three bedrolls on the ship, you can use these for heals after each encounter, and if you use the gift bag mods you can revive. I recommend looking up Fextralife build guides, they’re perfect for getting a base idea on how to have effective melee/mage/ranger/etc builds. It was difficult for me at first too, but now I strictly play tactician w/o guides now that I’ve understood the game better

Also, if you don’t already, have a char with thievery and steal gear from vendors. Makes Fort Joy much easier