One more thing to understand, that you might be missing,
UDP is unlike
TCP, in case of
TCP you can not send without checking the socket is ready to write/send, well you can but it might fail with error and ask you to block or to wait, UDP it is ready always, like always always, just SendTo and call it a day, it might fail or drop the packet but you don't have control about it as there is nothing to do about it, will not explain how to mitigate this here as it is irrelevant your case, 35 clients unless the traffic is saturating you connection it will work like charm.