I also had this thought. But really any gear that covers you completely and doesn't let sun through should work.

Is this not an option? I would thing it would be. Like a cowboy hat or a burka.

Or an umbrella, cloak, sunhat, SPF 3,000,000... i get that the sun is the only weakness to these damn near godlike pawns but having to micromanage against it is such a pain.

I've taken to just roofing over the entire map, also helps since I turn off the avoid sun AI because it bogs down my game.

Or at least have sun damage invalidated when Mechanoids block the sun over your colony.