"Null" Wifi options in Catalina 10.15.7 (imac late 2013)

My late 2013 imac had been working perfectly with catalina, until it needed a logic board replacement. When it returned from technical assistance, the wifi options disappeared, and in the system report two elements appear as "null", as shown in the photo. After racking my brains a lot trying to solve it, I found that when booting the mac with an external disk that has the previous Mojave system, the wifi appears perfectly and works normally. The problem is not the board, it's not hardware, it's a matter of conversation between Catalina 10.15.7 and the device that manages the wifi. Below are pictures describing the problem. I need a solution as it's the same system, same HD, same network settings, same router. Below is a list of what I've tried:

1) NVRAM reset - did it four times with no results

2) System reinstallation with the most recent version of Catalina - no results

3) "Clean" reinstallation of Catalina - the problem got worse

4) hardware diagnostics - it said that the wifi was not working

5) Boot with external disk Mojave Mac Os - wifi returns perfectly, making it clear that there are no problems with the hardware

6) Restoration via time machine of the entire system to the settings prior to the repair, still using catalina (the system downgrade is my last option and I will only do this if apple does not give me another way out) - no results

The final result of all this follows in the photos. If anyone can help, I appreciate it. I've been to the official and unofficial forums and no official or unofficial solution solved the problem. I've already heard that some of you had the same problem, followed by no solution. The topic is relatively old, though, so I'm hoping now there's something to do in order to save my wifi in Catalina.

Thanks

Marta

[Edited by Moderator]