I probably should learn how to beat this stupid strategy

You did fairly well tbh, I was expecting much worse from your pessimistic posting.

Your early game was pretty strong, you were making a lot of good decisions there. When it fell apart is when he porced the map up and you were going for an assault/raid mentality. Tanks cannot assault into JJ. They have placeholders, stardust, moderators.

Instead, you should try to make them come to you. Pillager can deal with the porc, moderator, firewalker, and placeholder no problem. Protect them well and grind them down.

With tank? Your best bet is Emissary behind porc. They murder moderators pretty well.
Everything else loses to them. Ogre and Minotaur in particular fare very badly.