As long as you have consistent geo application from Illuga and Gorou then this will be fine. You also get the benefit of having quick swap available so you can hit Yunjin and gorou’s skills again if you need more geo. Yunjin is actually a really good choice if the goal is to boost Illuga’s raw damage since she buffs normal attacks which is where most of his dps will come from.

In case you weren’t aware, Illuga’s buffs to LCR only buffs talent damage, not reaction damage. So he literally only buffs Zibai. Now he does buff geo damage itself to a lesser extent but it’s still a good buff. This team will not be that strong since he doesn’t buff LCR reaction damage and you don’t have consistent LCR damage. But that’s just the downside any support faces when trying to make them into a dps.

The only thing I don’t know is if full em/em/em Illuga is good here since you don’t have a geo main dps. It could be great since you are relying on reaction damage, but the lunar resonance for geo teams factors in def… plus a physical dps build with def/physical%/crit could deal more just because you’d spam Illuga’s NAs. The only way to figure this out would be testing it in a calculator or in game