KIA BESTA 2.7 spends a lot of water and heats up

I have a 2004 Kia ​​Besta 2.7. I replaced the head gasket, filters, seals, and radiator cap. I even had the cylinder head resurfaced, and they found nothing wrong with it. I changed the spark plugs and piston rings, but it's still having problems. I don't know what to do... It's using up all the coolant in the reservoir. I need urgent help! I've only had it for a month!

Is your car getting wet in the footwell (driver's or passenger's side)? Is the carpet wet? Is there steam coming from the vents? Check your heater core; it might be broken. If you can, disconnect the hoses that go into the car and see if it's still using heat.

Did you remove the thermostat? Maybe it's clogged, that's why it's overheating and there's overpressure; it might be leaking through the radiator cap.

The first thing to check is if the water is dripping onto the ground or is only being consumed. If it is only being consumed and not dripping, check the condition of the oil and water. If they are fine, your cylinder head may be cracked.

I changed the thermostat, had the cylinder head checked and tested, and everything is fine. The problem is that it starts to overheat, then I check the reservoir and it's full, but the next day it's empty, and the radiator is low on water. I don't know what to do; I'm desperate. Two weeks ago, it overheated a bit, and I had to replace a lot of engine parts, and mind you... I only buy original parts. The same goes for the head gasket. I changed the belts; I did a really good service. I wanted to get it running perfectly, but this is getting beyond me. I don't know what to do, and I need your help since you're experts on this. Thanks to everyone who offered their support!