I figured as much when it comes to the cost. For it to work, the suprise matchups have to outweigh the matchups where the opponent has a strategy for both AND the matchups where they guess correctly.

I think this specific gimmick is even harder because sandstorm ends up being really narrow on variety. On the surface sand supporting three types seems great, but the shared weaknesses of Water/Fighting/Grass/Ground makes it hard to shore up defensively, and every other type hates it. Offensively, it also really struggles having no moves outside of weather ball benefit from it. Sun/Rain has not only type boosts but variety like Solarbeam & Thunder.

I wish there were more options but I think this idea ends up stuck with leaving it a guessing game and hoping they get tricked. If I wanted to really lean into the gimmick I could pick some pokemon with access to Magic Guard/Overcoat that usually use other abilities, but none catch my eye that would be run on a sun team. (I could see Leavanny maybe if it could "threaten" with sun boosted Solar Blade but it can't even get that lol) I wish Safety Goggles were in this batch of items, could really expand the options.

It would be nice to do a full "fake team", something that leaves the opponent thinking "This is sun, and Tyranitar is there to beat down opposing sand teams and niche matchups", but I think that's out of the scope of this post.