Is not say more expensive AIO bro.
Difference between 240 and 360 cooling will be maginal better.
Cuz the radiator is longer and additional one more fan.
The way you setup looks weird also, the top is meant for 360 but you only
put 240.
Actually the 240 radiator you should put towards the end of the case.
That fan can put in front.
Most setup the radiator is place like this so hot air can escape quickly.
Not sure what case fan you are using, hopefully is not Tecware fan.
360 AIO wise there are some budget option like this Corsair new model AIO.
Around $150.
You can try with a 360 cooler like this, three fans to exhaust more hot air out than 2.