Main thing you need is a stress healer early on. So at first inn get the plague doctor upgrade for ounce of prevention.
Game isn't too difficult after that.
They did buff the late game enemies somewhat making it harder to win but the rest of the game shouldn't be too hard.
You don't need to clear the lairs all the time. The bosses there are very strong in early game. Go for the first two fights and then leave. That should help a lot.
Yes, most of the time it's not that hard, and I always have at least one stress heal character, often two.
Having the plague doctor be almost obligatory isn't that fun, though. I can't seem to find a good way to make the Jester good enough to replace her yet. Maybe it has really good stress reduction skills which I haven't unlocked yet? I choose a lot of the same characters over and over since they must be able to overcome all challenges. And then I don't unlock new skills for the other ones.
It's only two out of maybe ten runs I've gotten the "meltdown of doom spiral". And both times it was against regular enemies (the cosmic big ones, two encounters in a row one time and the monster that does skull toss and howl, several regular encounters the other run), which are really annoying and cause a lot of stress. I had almost no stress before those encounters, and every character hating every other after those. I managed to get to the mountain one of those times, but it wasn't fun with regular negative banter and interrupts and a guaranteed loss against the boss. (BTW, the final boss is not very fun to me. Very grindy.)
It's still quite fun, but I feel like I've seen most things available this far into the development. I'll try it again eventually.