Running without a thermostat ok?

They call it a cooling system for a reason. Once you start removing parts of that system, the problems start showing up. We have been through this hundreds of times on here.

My car, running a complete factory cooling system, with an AC condenser in front of the radiator, could idle all day, on a 100 degree day, without overheating.

Get the correct thermostat, use a fan shroud, use a real fan that can move some air, have an adequately sized radiator in good condition, use a good and correct cap, and run coolant.