I don't think it has to effect the story. The story after it hasn't cared about the 5 years time jump, much for any large point. And if the characters can remember, that maintains the personal drama connected to it. With the stones, I think it can be done, and everyone who was born in that time can be maintained, including Morgan.
Not just to accommodate 1 actor. I prefer it for other reasons. But in this case, I'm suggesting it for this.
It's for a character that was in the first 2 Ant-Man movies.
They don't have to recast. It doesn't have to be not worth the time. I see no reason to not do it.