i replaced the waterheater +thermostat and still over heats

The thermostat is in correctly here the thing also. When it says it's hot after I drove it for a bit I can still take the cap off there's no pressure or antifreeze coming out like a volcano. It just flows out slowly

Your fan is a clutch fan it turn it with serpentine belt. Did you replace the cooling fan sensor and the cooling temp sensor? Let me know on this then I can link you a diagram

No I did not replace any of them sensors. Well that also be the cause to why at an idle my oil pressure drops then goes back up when. I give it gas

Cooling temp sensor and cooling fan sensor they work together Cooling temp sensor when it's getting hot it will send a signal to the cooling fan sensor and cooling fan sensor Will tell the engine idle up a little to spin the fan clutch more And your oil it's your oil pressure sending unit sensor that located on your engine block

Yes it safe to drive. ??

No

What if they said the sensors don't cause them readings and they blam it on the instrument cluster