Why is Kun's song not a solo but ended up being a unit release?

I love the idea of a collab, but when it was talked about in April, Kun was the only name mentioned so I thought it was going to be a solo like Mark's. Kinda disappointed but was hoping this was Kun's moment to shine with all the delays. They should've said it from the beginning if it was going to be a unit release. I was really looking forward to a Kun's solo lab. He deserves his moment in the spotlight after being shafted for so long.