Running 10.15.7 with "Allow apps downloaded from: Anywhere" selected...

I d/l'ed v 4, opened the .dmg, and launched the installer with no problems.

I've got no idea what your problem may be.

Also, I checked the required specs, and you're OK in that respect.

Maybe try a fresh d/l?

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire