I think it's really interesting to see this question come up and I hope that people gave some helpful thoughts in the comments. I build my teams really weird tho so I'm gonna blab a bit xD
I have a thing where in any of my hoyo games, my DPS needs to be in the first slot, event if its not optimized. Genshin, ZZZ, even Honkai (tho I've recently been corrected on that habit in that game due to AOE dmg and.. anyway).
The reason this isn't an issue for me in ZZZ is because I play on controller, where it's a lot easier to swap characters in both directions, as opposed to M&K where you mainly swap left to right. So for example, I'll have Yixuan slot one, Fufu slot two, Astra slot three. I'll start the fight by swapping back to Astra to get her skill going, then backswap again to Fufu to start her stun, and then from there swap when needed between Fufu and Yixuan with Astra's skill.
IF I were to play on M&K though, I'd probably order my team in a logical swap order. Astra/my support in first slot to apply their ability first, then my dps/stun/etc where needed. With certain characters like Seth, after they use their ability their swap goes to the person before them in the order, so if I was using Jane/Seth on a team, I'd want to put Jane left of Seth so I could swap to her after his skill.
Learning what characters switch to what other characters matters a lot more on M&K than on controller, so keep that in mind! And (apologies for the self promo) but I've started posting builds on TikTok and on my Discord if you need to know anything about swap orders, and if you're having questions feel free to @ me or message me, I'd be happy to help :3
Is putting your agents in certain slots matter?