@solobsd hi, I even used Qubes OS with 8 GB of memory, it is tight but it works.

All qubes (VMs) are created with a swap, this allows running with a bit less memory if you have a fast drive.

Finally, Xen offers memory ballooning, you can give a minimum memory allocation to each qubes, and a maximum. Depending on the use and required memory, the ballooning will try to allocate the memory where it is required the most until you do not need it. It is not perfect, but it allows to have some margin without allocating a whole chunk for the whole VM lifetime.

Qubes do not need to run everything, so most of the time 1 GB per qube can be enough to run a program in it, there is desktop environment to run within too.

@solobsd thank you!