Shroud is currently at a Immortal 3 rank, which means you could play a ranked match against Shroud if you are at least in a Diamond 3 rank. Besides, as Shroud is from California, he most likely plays on a US West server. That said, if you are not from a North America region, there is no way you can play Valorant against Shroud, unless you change regions.
What Was Shroud's Peak Valorant rank?
Shroud has peaked at a Radiant rank with 608 RR, back in Episode 3 Act 1 (Summer 2021). As he stated on one of his streams, Shroud is not interested in climbing Valorant ranks as much anymore, as it just takes too much time, and viewers are not really into it. Plus, as Valorant community can be toxic, especially when you are dealing with stream-sniping, and spending too much time with the tryhard community on ranked... every lost game just hits different on your mental health, it just has to.