DOKS - add a route on the node for bridging networks

I wanted to bridge k8 networks between digital ocean and other cloud providers. After doing a lot of research, I suspect the easiest way is to set up a small k3s droplet and get the DOKS cluster to send traffic for the new bridged over network to the k3s droplet.

As far as I can tell all I need to do is set up a route for this new network - lets call it “A”, for example 10.250.0.0/16 - on each of the DOKS nodes pointing to the new droplet running k3s.

Think of something like https://docs.digitalocean.com/products/networking/vpc/resources/droplet-as-gateway/ but not for ‘default’ but for network A only.

I have figured out how to login to each of the DOKS worker nodes, but of course any changes I do won’t be persisted across upgrades.

My ultimate end goal is to allow a k8s cluster (running k3s possibly) on a different cloud provider to talk to my DOKS services, but securely via VPN. Ingress and public network connections freak me out!