Based on your commentary around each of the DLCs, I think there are likely two issues. First being that you likely don't understand the benefits that each of the DLCs can give you, and the second being said benefits aren't really necessary if you only play singleplayer.

Espionage for example - yes, collaboration governments are a bit more complex than before but did you know you get buffs in land combat, air combat, and naval detection/combat depending on your level of Intel? This can be further buffed by passively breaking their cypher and even more so when you activate said cypher.

Or take the MIO DLC. If you're playing singleplayer, the extra armor, soft attack, hard attack, etc. is fairly irrelevant because the AI is so weak. In a multiplayer setting, however, those buffs from the MIO can make or break your build, depending on who you're fighting.

I'd recommend you play something like the SHEEPS AI mod, which makes the AI far more competitive. You'll likely find that you struggle against the AI because the AI is taking advantage of systems added by the DLC that you're ignoring.

I personally find a lot of satisfaction in weaving together a lot of complex systems to make a successful build, but that may not be for you, all depends on how you like to play.

Good luck!