What should I do next?

Right now I’m at tier 12 (I don’t make it very far tho) and I can make it to around round 2900 on tier 1. I’ve got every upgrade unlocked except the last attack one, I have 4 lab spots, 12 card spots, not every card unlocked, and 4 ultimate weapons which might not all be the best. What workshop upgrades should I prioritize at this point, and what should I use my gems on? Last lab spot, more card slots, or trying to unlock all the cards?