As I know, there is no alternative app like vmos for now, VMOS is the only app on Android which can double your system.
But if you want to know if there is an alternative app like vmos not on Android, I may say Emulator is a good choice.
About Android emulators on pc, you can visit this post 5 best Android emulators for pc 2020.
Actually, there is another way to get a full control Android system, and more than that, you can use the latest Android system, which is better than vmos or any Android emulator.
Bliss ROM is an Open Source OS, based on Android, that incorporates many customizations, options and added security features.
And it is available for just about any Chromebook, Windows/Linux PC or tablet released in the last 4 years, So if you just want an Android system, this will be your best choice.
How to use Bliss ROM
There are two ways to use Bliss ROM, one is install it on your PC like install Windows which I don’t suggest, another way is use a virtual machine, just like use vmos app on Android.
You can download VirtualBox or VMware, the difference is VB is free, Then turn on your VT mode on your BIOS.
After that, you can use VirtualBox load Bliss ROM, And you will have an Android System on your PC.
VirtualBox Download: VirtualBox for windows
Bliss ROM Download: Bliss ROM for x86 Devices