You should skip down to the end of the VirtualBox article. "This isn’t the fastest way to run Android apps on your PC—BlueStacks is faster..."
Here's an article discussing a few other emulators.
It mentions MEmu Play, where the focus is on gaming. "To get the best performance, it is recommended that you enable virtualization for your CPU."
It could be that your PC is just too slow to run the games you want to play. Emulators add a lot of overhead, especially when are translating instructions for one chip-set to a completely different processor family.
I set up a PC for someone using BlueStacks and MEmu at various times. I didn't notice any difference in performance, but I just used the PC long enough to make sure it worked.