Congrats. Now go playing TFTD.
Replaying Xcom immediately would burn you out. Superior difficulties mean simply there is less space for mistakes and Aliens ramp up their attacks quite faster. I've had base attacks after Laser Rifles in Superhuman.
On the other hand, TFTD is quite similar, bar a tileset that I like a lot more and several choices that make it a far harsher beast to win. It's winnable in any case, simply.... a tad more complex. To make you understand without spoilers:
+ No Laser tech. You don't get unlimited ammo weaponry.
+ No smoke grenades. Ink grenades are bugged. And they don't work abovewater.
+ Two-maps missions. That means that several missions require to clear you two maps worthy of foes. Sometimes you get even 30-40 aliens.
+ Some enemies are
considerably tougher. Luckily, spawn tables are borked.
+ While Xcom had "Better weapon, more ammo" TFTD works the opposite. More powerful weapons have less ammo and everything weights a ton. The most effective gun, the equivalent to the Plasma pistol, will get no ammo in a short while.
+
Bio Drones
So I played through the entire gaming without ever needing a second clip of ammo, never having a soldier's morale fail (even the low Bravery ones I used as scouts, and not counting Psionic attacks), nor having a base invaded (I saw some Battleships whizzing back and forth; were they searching for my bases?).
Did I miss something? Or did I just play too cautiously, or was I just lucky? I had a fair share of competent soldiers dying, so it was not like I played like a superman.
Xcom is not that hard if played smartly and on an adequate difficulty level. I may add that even Superhuman is not too harsh, if played with a bit of salt. Something like the basic Episodes of Doom: it's a given you play them in Ultra-Violence or Nightmare!.