All spawners can be shot and destroyed by bow and arrow from afar.

If you have trouble with melee enemies, you can use the polearm weapons (not spear but Atgeir) and use its secondairy attack to swing it around you and knock enemies back.
Works decently well near spawners as well, pushing enemies back while hitting the spawner.

Never rush into rooms of dungeons, go back to the beginning if you have to, and you can always leave the dungeon when things get too hard.

If you leave a cave or dungeon, the enemy will get disinterested and walk back after a while. You can see if you still have agro from an enemy in a crypt/dungeon/cave, by crouching down. (stealth) you can see the ''spotted'' eye close when enemies lose interest, some time after that they start moving around again, going back to the place they were.
Giving you the much needed time to heal up and jump back into the dungeon.

If you have debuffs like being wet, or lost your rested buff (that gives stamina and health regen), you can always build a campfire near the dungeon and get the bonuses again.

Hope this helps, dont listen to those people that are hurt by you using cheats, if that is your way of enjoying the game power to you.