I haven't played endless games with Hungary, but I think most people use the suzerainity bonus incorrectly for the early game. Early to mid game suzerainity shouldn't be about war. It should be about money...more specifically making the city state pay for themselves and not getting them killed in the process. Early game the goal of any city state manager should be to pillage (with the appropriate bonus policy card of course) a chosen AI as much as you can without losing units. From tile yields, to goody huts, trade routes, or barb camp clearing...if it's not nailed down you take it. Which should not be too hard since all of your units have 4 movement. Think of yourself as a barb camp and burn the place down. Never fight unless trapped or an easy win. Stay away from city centers or encampments. Never upgrade your units since this does nothing for their movement for the most part and it is the job of the city state to do when they get their units back. Pillaging yields early game far outweigh anything you could hope to do by taking one measly city. And whilst pillaging their entire countryside you're fairly likely to capture a few rogue builders/settlers which is critical in continuing your own development. Remember, you've got 30 turns to play cat and mouse games... Once your units have no other viable targets, surround a city and make them pay through the nose for peace. Or, use the last turn before peace to pillage tiles directly next go city centers. Make peace and watch your boys make the long walk home. They'll spend generations trying to fix the damage you'll do.This strategy can even work while not at war. Last game I played I levied a city state, marched about 6 swordsmen up to Dido's borders and entered the diplomacy screen. Dido paid me 95 gold a turn, 31 gold on the spot, 23 diplomatic favor, and amber in order to instead start a joint war with her and I against Peter (who was not even close to either of us and was no threat.) I later used the nearly 3000 gold she paid me (with Amani's help) to take suzerainity of her city states and crush her like a grape from both sides of her empire's flanks. Plus the leftover 1500 gold that didn't fund her own demise went to good use as well. Priorititize suzerainity over city states that are unlikely to be frequently attacked by the AI and yet have proximity enough to act as murder for hire. Trade city states will pay you the money needed to repeat the process more frequently. That should turn things around for you. Hope it helps.