best thing I can tell you is this: You can spend 40 hours on the island the game starts you on.
It's like, one of four worldspaces you'll go to. So, unless you're the type to drop 100 hours into an RPG... don't spend 40 hours at Fort Joy.
Unless you want to.
Or unless the chapter boss dribbles your corpse a few times, in which case... probably level up more.
Oh. And the world is not your friend. It will be used against you. Be mindful of all the environmental interaction/elemental intricacies. Because the AI will eventually use them against you, either on purpose or by accident. And the dead last thing you want to do is be stunned when you didn't intend to be.
Oh. Also also. Diversify your damage on your team. Be able to do physical and magical damage, hopefully in equal measures. Some enemies will be more susceptible to one or the other, and nothing worse than running into someone with all the physical armor and no magical almost on a team full of melee attackers. Literally nothing worse. Except when that someone drops oil on your team to slow them, then lights it on fire and your idiot team of melee attackers can't move enough to get out of the fire, nevermind to attack the a$$hole raining fire down.
This didn't happen to me, but I watched it happen to a friend. It was hilarious. He never played again. Don't be like him. If at first, you don't succeed, die, die again. Or, use your brain. Or cheese the game by playing undead and dropping deathfog on things you hate

Do you, cuh. It's an RPG, and Larian is gonna bake Baldur's Gate 3 fukking crazy, because they love letting you do shyt you might not thing is possible/doable but is.
(Steal. Steal everything. Coins. Equipment. Lives. Buy things you don't need, steal your money back and then sell the things you bought to someone else. Thievery is the answer to every available problem and a few unavailable ones.)
But on the real... play some of Fort Joy, learn some stuff, scrap everything and start over with what you've learned. It's better that way. Also, understand that about half of Fort Joy is tutorial. The game doesn't really become the game until your collar's off.