It cost me it or install Catalina 10.15.1. He was watching a thousand videos google making a usb ... somewhat special, with two partitions, FAT again and MAC other ... crazy ... but it worked after adding in Cl over installation of the USB NPCI instruction = 2000 ... and it worked.
Then I could not upgrade to 10.15.2 with C lover or update the same C lover beyond version 5100.
I confess that I made a paste copy of Open Core of a hardware similar to me or (Ryzen 5 2200G and Msi B450 and XFX x590 with firmware changed to powercolor ) ... and the first. The only curious thing is that he skipped 10.15.2 and installed 10.15.3 directly.
In one SSD I have 10.15.1 and everything works ... in the other SSD 10.15.3 and siri does not work, the sound via bluetooth flutters from time to time and I notice something slower ... it scares me play OC because I'm clumsy with balls ...;)
sorry for my inglish.
Spain