Can I connect a servers from Hetzner cloud to a vswitch
Solution 1:
Before it was not possible but as of today (Nov. 2020) it is possible:
Yes, you can connect your Robot vSwitch (dedicated servers) with your Hetzner Cloud Network. Create a new subnet in your Cloud Network and select the "Enable dedicated server vSwitch Connection" checkbox.
There is a tutorial referenced as well
Solution 2:
As of today you can, this feature have been implemented. You can read more about it here:
https://docs.hetzner.com/cloud/networks/connect-dedi-vswitch/