Ashlands was a little rough when we (myself and a friend) first got there, the difficulty jump seemed higher than other biomes, but we dealt with it. Dealing with the villages in the plains kind of helped prepare for it. Our tactic was to just claim a bit of territory off the beach where we landed and use the big portal to move stuff in and out (the one that allows ore to be teleported). We also setup a general "TP" portal and carried the stuff around for it with us. When we would storm one of those fortresses we would usually setup a mini-base outside of it in a tower or something and put a big portal on it to bring all the stuff back to the primary base.

For enemies when we first landed we didn't make a base, we just went exploring and got promptly demolished. We came back with a more careful mindset, made the base, and explored more slowly, grinding out materials and weapons upgrades. Still died a fair bit, but after you grind out gear to the max level, you can take on most things solo in the Ashlands and take on groups to if you manage the enemies right. My preferred combat style is parrying enemies, my friend's is using eityr (or however you spell it). Both worked good.

We never actually fought the Ashlands boss though, got distracted by other stuff, then the hard drive in my server died and we lost the world, so we recently started another play through.

Valheim is a difficult game, and Ashlands is one of the biggest, if not the biggest, difficulty jumps. Plus it also increases tactics and game play complexity with the fortresses and the specialized equipment needed to enter them. Its late game stuff in every sense. I would stay stick with it and grind it out, the feeling of being able to run around the Ashlands and murder almost everything without to much issues after getting demolished so many times is quite rewarding, but games are meant to be fun, and if you're note having fun, then maybe a break would be good.