I'm always using a virtual machine for Android to test and there is really nothing reasonably clean on the Internet.
Here is now a virtual machine for VirtualBox. My current version of VirtualBox is 6.06.
Download. Unpack. Import. And then have fun with it.
If you want to do it by yourself then the VM has to stand for about 1 to 2 hours after installation. The same is with flashing ROM's on the phone. Do not touch for 20 minutes after flashing. Please do not ask me why this is so on Android. Thus, the VM is ready to use.
Here the link:
The VM is 100% free of virus, spyware and other things like that as far as supplied by the manufacturer as such. The VM is already rooted, which was also done by the manufacturer. The root (system) directory is "read / write" by default.
Would be glad if suggestions for improvements, changes or other settings will come from your side to make this machine better.
Hope you enjoy this.