My understanding of a typical shieldless build is that they run cold and rely on not being detected and rarely getting hit above tanking due to high armour. Is that wrong? I have, inexpertly, tinkered with shieldless builds in the past, but thought I took a lot more damage? Also, Thargoid damage is absolute right, so resistances on shields or hull make no difference.
In my AX Support Anaconda build, I had great hull, great shields - Prismatic, pure shield health, no augmented resistances - and it was a VERY survivable build. Shields seemed to ensure that not too much damage got to the hull and, if shields went down, I could still tank for a bit. I had repair limpets and AFM so could repair hull and modules as needed. Also had anti-caustic limpets. Only issue with the build was that limpets would die the instant the ship took fire, so I had to escape to repair - not so easy in a slow ship. Still, it was designed to work as part of a team, allowing other ships to focus more on the killing part with less compromises. Ended up never using it in that role as regular wingmate had zero interest in Thargoid stuff.
Medium ships do seem to be lacking the space for all the things I'd think I'd need. However, I understand they're considered the METa for AX work. I did really quite like using the Anaconda build I did, but it was just way too slow to work solo. I thought it'd hold its own with AX NPC's in the instance too, but they would ALWAYS bug out seconds after I arrived in an instance when I was doing regular Thargoid stuff prior to the Titans.