Android emulator - Security & Privacy - allow apps

Hi everybody.

I'm trying to install, without success, an Android emulator on my iMac.

First tried Blue Stacks, but the installation goes timeout waiting for my approval under Settings -> Security & Privacy -> General, it never asks me to allow the app, it never show up any "allow" button.

Now I'm trying to install Nox, but two problems arise here: first, the installer is in Chinese language, strange because I download first in English, than in Italian (I'm from Italy), the installer was nevertheless marked with a final "_en"; second problem, the installation process is stuck at 99%, and searching online I found that the given solution is, again, allow the application under Settings -> Security & Privacy.

https://www.bignox.com/blog/fix-nox-app-player-mac-version-wont-start-issue-stuck-99-issue/

Needles to say, I can't see any "allow" button in neither cases...

What can / should I do? I could try another Android emulator, but I'm starting to fear that I have some problem in my operating system, preventing me to allow third party apps.

Thanks for your help.