I use ZeroTier for my site-to-site VPN on my Ubiquiti devices, but the ZeroTier packages are quite old. In this post, I log my adventures on getting an updated arm64 binary for these devices.
I revisited my inter-site VPN setup after migrating off of Windows Server 2012 R2. I explore using ZeroTier as the VPN alongside IP routing on Linux, using an existing VM and Raspberry Pi.