Art of war against the Huns: build a thin city in an almost inaccessible location and palisade it, put an army to guard the sole approach path so they can't initiate a siege but have to start a battle, then get the hell out of the city asap and use some archers to have a target practice on moving targets from the safety of behind the city.
This way won me two wars and let me to cling to the map somehow so far

AI did not bring in too many infantry and when they did bring them, they pressed them against the cliffs to be massacred rather than to try to get into the city itself.
After a few runs on Civilization, the next easier than the previous, I thought I'll finally try the Humankind difficulty, and, first game, I'm barely clinging to what I managed to grab, and that's not much

Sandwiched between three civs, got myself a thin and long stretch of land north-to-south across the landmass, and my western neighbour honoured me with two wars already. Lewis AI persona btw, man, is he an aggressive bully
My capital Aššur hardly had any productive turns during late Ancient and most of the Classical eras, almost all turns were spent in the battle lockup.
And those were full 6 turn battles, then a turn of a respite to push out a couple of replacement units, and then a new carpet of huns arrive.
Battle after battle, to slowly swing the war support score around until they surrender. It's a death sentence to stay within the city tiles, those cycling horse archers do chip away the garrisons pretty quickly. Luckily, the terrain gives me massive advantage, vital cliffs everywhere, and AI did not try to use the available southern way around for some reason, they just pressed against the western walls.
So two wars won, but dark clouds over the horizon did not get any lighter. My southern neighbour vassalized my eastern neighbour, and, although I converted to their religion upon request and I had very helpful trades during my first war, they demanded my second city to the south during my second war and all the trades stopped, so there's uneasy peace now and they're vastly stronger than I.
But I hope, this is fine. I'll try to show them something Byzantine during my Medieval era
