Looked into Stronghold and Settlers but I never played any games from either series.

Empire Earth, perhaps?

There are a couple. Most of the games have more in common with something like "Rise of Nations.", but as for the purest form you can get similar to Age of Empires, I would go with "Stronghold HD" "Total Annihilation", and "The Nations". Stronghold seems the closest to Age of Empires 2 with a focus on Siege Warfare. The nation is cartoonish but seems very similar otherwise to the old games.

Empire Earth 1 is the most like Age of Empires I would say. I would also say it is better so you should give it a go at least. They gave it away free at one point if you want to wait and see if that happens again! :D

I just started playing Settlers 3. It's addictive to the point of insanity, but it's NOT LIKE aoe.

Dark Reign is close to AOE but to be honest I always felt it was way too fast. I like tme to build up and plan attacks. DR is just constant attacking or being attacked, even on 'easy'.