Sorry about that – you're right, I made the Tidal South too hard. In the latest patch on my website (towerandtrail.com), this map is now a great place to hunt for strong gear, and I've also made a small balance change to make the characters a bit stronger. If you want your team to get through more easily, try 2 Mages, a tough Warrior as the tank, and a Bow as your main damage – it helps a lot.
Just a note: updates on itch.io come a little later than on the website, as I mentioned on the game page.