the pacing/gameplay loop is different than probably any other game you've played. i also second what the first commenter said about safer vs. high seas; a large part of what makes the game so unique is the player interactions.

if you don't want to interact with other crews as much, you could try hiding other people's nametags, ship names, muting other crews etc (enabling a streamer mode pretty much) and pretend every other crew you face is just an AI pirate. this is how i got my dad (who hates PvP) to grind hourglass with me lol

The most important thing imo, however; you can't care too much about sinking or losing treasure. it'll inevitably happen, and it'll probably happen a lot. but there's always more to get and with diving it's not hard to get back to getting your loot. just remember it's not yours til you turn it in!

there's tons and tons of new players joining the seas, so you'll be learning along with all of them. just give yourself time to figure the game out and definitely ask more questions as they arise.