For me, swapping jewelery was the final trick to play if my teams turned out to be too weak to 3-medal the Winter Rose Garden maps.
As it turned out, I didn't have to use it, even though sometimes a team perished.
In the end, it came down to the RNG nodes and some team reshuffling if the initial attempt failed - and so I managed to 3-medal all the current maps by 2-4 tries.
This was my squad configuration:


Oh, and I needed to keep tabs on the Solar Blast since this time around it actually made quite a difference.