Get 64GB. 32GB will not cut it for 3 VMs with 8GB each.

Three VMs with 8GB each is 24GB just for the guests. Your host operating system, background apps, and overhead from virtualization (memory ballooning, etc.) easily eat another 8–12GB. That puts you right at or over 32GB before you even open a browser tab. You will constantly hit swap, the system will slow to a crawl, and those VMs will be unusable.

32GB is fine for one or two VMs. But three? You need headroom. 64GB lets you run them comfortably, give each VM some extra breathing room for spikes, and still have RAM left for your own work. It is not about being safe; it is about not hating life every time you boot your lab.

Future you, who is not staring at a beachball while waiting for a VM to respond, will thank you.