2008 Chevy Astra – Strong smell of fuel and other issues

hey! im having this issue with my car that i have some ideas where to start but I would like to have some input from you guys.

2008 Chevy Astra (Opel for Europeans)
2.0 inline 4 SOHC Gas Its an old GM Family 2 engine. (X20XE)
80k miles, I own it since it was 60k. All the maintenance done correctly and in time by me.

Symptoms:

VERY strong smell of fuel coming of the exhaust. Not only when recently started. Always that is the engine running.
Car feels a little bit low on power. Especially with AC, which i do know is normal but with the AC on is a snail.
There is some ocasional stutter or like a very little miss that you can hear in the exhaust.
Fuel consumption is not bad, at least not noticeable I am getting 24 MPG.

Sometimes the car starts and shoots up to 1200 RPM when cold and when driven, it feels like it pushes really good. Then the majority of times it starts really rough and stays at 500 RPM for a few seconds and then normalizes and stays at 800 rpm, even when the engine is super cold, when started that way, it feels a bit low on power when on the road.

Things already done: Plugs, wires, coils, air filter, inyectors cleaned and tested ok. Plugs look fairly good and even. I have a scanner, fuel trims seem ok nothing abnormal there. Also O2 sensor seems responsive enough and no codes present or stored.

What baffles me is that fuel trims are normal but i think car is definetely running rich. And ofc, i checked for fuel leaks and there is none.

Any word of advice is greatly appreciated.