Currently my environment is configured VSAN network gateway in firewall level. Whenever the firewall or core switches maintenance activities are there, we have to shutdown in my VSAN environment.
Instead of this solution, we are planning to configure dedicate Network Switch will connect vSAN ports.
My question is that, the dedicate network switch is the best configuration to avoid this scenario?
The second question is that ESXi management network also will be reachable to make up and running VSAN environment.
Sure. That is a good way of avoiding the situation. Other customers simply have a non-routed VLAN and leave it at that, but if that is not an option a dedicated switch is, of course, a solution to get around it. With regards to the management network, you don't need to have that on the same switch.