i saw many 5500xt that can do around 29mh at 50 watts.
Maybe someone have one for me for tests?

It looks like that this is data from HiveOS or RaveOS, it isn`t correct. You need to use a wattmeter to get true values with AMD GPUs.
my better 5500xt do 27 mh at 53-55 watts.
my lessor ones do 25 mh at 51 watts
I only do memory straps
I never flash bios.
My 5500xt are about 28mh at 75-80watts, only RaveOS configured. My 5600xt are flashed and about 43mh at 100-110watts. Before flashing 5600xt gave me about 39-40mh with the same power consumption.