In my office I have 3 internet connections with 3 different ISPs. My PC (Windows 10) is connected to all 3 connections with 3 different NICs. Is it possible to run three instances of Zerotier and join the same network three times (with different IPs) and make sure that each instance is only using its dedicated network card?
Windows can’t run multiple instances of ZeroTier. You’d have to use 2 or 3 VMs. You could give each VM access to only one of the NICs.
If you’re trying to do some kind of load balancing, Multipath | ZeroTier Documentation might be a different way.