As I read it you’ve replaced parts in several areas of the car, which says you have not yet identified where the leak is coming from. It is somewhere near the front of the motor, that’s about all I can gather. Oil leaks travel, meaning the oil comes out one place and drips on the floor at another. It can travel down a hose, like an oil cooling line between the motor and radiator, it can start at the top of the motor and dip all the way down and to the side before hitting the floor. You need to get the car on a lift and see what is wet and trace the fluid back from where it drips to the source. This may take cleaning off surfaces and checking them again a few times before you finally figure it out. I won’t replace a head gasket or get into expensive work until you know where the leak’s source is located.
You seem to suspect the valve cover. Perhaps it is warped or damaged and still not sealing up even with a new gasket.
Clean as much of the oil off the motor and frame of the car as you can and see what you learn in the process.