Is it possible to reserve a server in a certain region? Doing this for matchmaking to match people in a close region or select a specific region.
Unfortunately this is not possible yet. Roblox puts each client into servers that work best for the player, with the least amount of delay (least ping possible in short). Although I do agree it would be a neat addition!
I wouldn’t worry too much about players going against players from far regions considering Roblox automatic allocation.