there is certainly a distinct lack of Robert players all around. Probably the one name that jumps out immediately for high level play is Azuki Neko from Japan, since he's one of the few that actually mains him and there's a decent amount of footage of his play available. Lacid from CafeID, Korea seems to play him sporadically, but the few times I've seen him use Robert he's done well. You're gonna have to dig really hard into the CafeID Twitch channel to find Robert footage, however. From France there is Tom Sawyer, and he put in work with Robert at the very recent World Game Cup.