VELOP doesn't have this built in firewall capability of blocking or rerouting traffic. At least not a feature on my Velop units.
In addition, I haven't seen on VELOP any capability of forcing a device to a specific node. Some Mesh will have this feature (Ubiquiti does), but not the VELOP. one of the issues I had that forced me to replace mine. Devices would do exactly as you point out, connect to the furthest node and result in kbps speeds.
honestly, said it above, I'll repeat it again: VELOP is a terribly designed product that should be garbage binned. there are much better products out there.