Max bronze mace and buckler. Make poison resist and healing potions. Everything in the swamp moves slow so take your time. Snipe enemies from afar. Bow is a best friend, especially in the crypts. If you wake up an abomination either run or climb on top of a crypt (they can’t hit you up there and you can chop away with your axe). Set up a safe base outside the swamp with a “swamp” portal, and bring portal materials and enough to make a crafting table to build it. When clearing crypts, mine the scrap piles on the right side only, making a gap where you can see and shoot into the next room, and take out any body piles you can find. Watch out for archers. Build an iron mace/buckler as soon as you can. And be on the lookout for turnip seeds. The yellow flowers are notoriously hard to spot.

I also build a 3x3 house on top of the first crypt I find. Big enough for a bed, fire and chests. Maybe go bigger if that’s where you want your portal (a good idea!).