What ip range to choose for the local network?

Question

Computer networks

I have several hypervisors running esxi. Now each of them has 1 virtual router that looks at the Internet, all other virtual machines communicate with the VM router via the 192.168.* network.
I would like to set up a VPN to combine all hypervisors into one network, I chose L2TP as a tool. The issue is that in all the manuals, networks behind NAT usually look like 10.*.*, and I have never seen 192.168.*.
Does it make sense to set up a local network on each hypervisor between the VM router and other virtual machines as 10.*.*, or leave 192.168 on each of them, and when connected to a VPN with the advent of a new interface, they will have one more address like 10. *.*?