There is part of the main story that requires you to use a settlement but for the most part I would say you can play it mostly as an FPS? Crafting is perhaps the least "optional" in the sense of switching mods to optimize your gear, but even then I suppose you could adhere to an extreme "use only what you find, as you found it" ethos. Mostly it will limit the usefulness of random legendary gear. But you do not strictly need legendary gear to play the game.
You don't strictly need to craft either it's a convenience thing.
You just need to find or buy the weapon with the modification you want, take it off and put it on the weapon you like.
It's harder doing this with energy weapons and DLC weapons.
Crafting isn't as monotonous as building.
Another reason to skip crafting is low SPECIAL stats eg idiot savant and 1 intelligence.
If you're going to extreme levels eg over 50 or perhaps 100 you'll find everything you need and crafting is a waste of perks.
If you're playing lower level and not using DLC craftingbis more damage now.
Explosive weapons get all the glory but sonething like a knee capping or wounding weapon is more broken if you find it early. If you get such a weapon early appeal of crafting goes down. If you're playing high level it's not needed.
Armor is also an exception you probably want to take it.
It's also why I said charisma and intelligence are the best stats. Crafting makes the game easier, faster, more convenient. Building gives you resources.
If you're roleplaying extreme survival mode you keep what you kill and eat or drink what you find. Interesting want to play when you've done everything and can one shot the toughest fog crawler in the game using a non legendary unmodified tire iron.
Or you try clearing the glowing sea level 80 using said Tyre iron naked.
Another extreme way is level 50 or whatever without leaving Sanctuary.
Or merchant prince with all the elite vendors.
Mostly because you've basically done everything all the meta builds, fun builds, interesting builds and want to test how absurd you can make it eg head to nuka world lowest level you can.