I'm gladly used to employing my Solar Blast, and in cases like these, where some of my teams may be just a tad too weak, I use it to specifically help those weaker teams. For helper teams, I developed a strong preference for teams with Strawberry Candle (who has a passive for 2-3 extra solar nodes, worth half a bar each), Cattleya or Mei Pumblossom (both have a passive to add 50% to your Solar Blast bar at the start of the map, and yes, it stacks!).

I got a bit tired of the RNG though, so just an hour ago, I decided to no longer bother with 3-medalling those maps. Once we get bloomed forms, I'll be farming these maps into oblivion anyway for materials, so chances are, that I'll get those 3-medal runs while farming.