Basics: Raspberry Pi Zero w with relay. Relay trips without input
You're not the only one who's complaining. I suppose is about this module or similar:



I see this isuue over and over, the answer is the same as here, the bad design of the module, the driver transistor base is left floating which makes it sensitive to EM noises. If you have some soldering skills you can put a 1k ohm resistor from the pin 3 of the optocoupler to the ground (transistor emitter). Somebody should be fired for releasing such a crappy design.

Edit using updated quesstion, the pushbutton needs also a stronger pullup, put a 1 kohm resistor from the gpio pin to 3.3V.