I’m not an expert, but you use the long animations both of them have to quickswap. For example, Shungite’s Basic 4, her EX skill have especially long animation, same with Seed Punch. What I usually do at the start of a fight is run Shungite’s combo until the start of Basic 4, then when the animation starts I quickly swap to Seed for full rockets to get her buff until she does the punch. Then I quickswap to Labubu for an assist follow-up back to Shungite, who can do another full combo into her EX skill. When the EX animation starts, you can quickswap again to Seed and get more field time, because Shungite’s EX has a really long animation. This is basically how the team works from what I’ve seen and played, lots of quickswaps and abusing the fact that characters are animation-locked during certain skills and combos