What kind of cardigan would you get for this dress?

I’m having a wedding celebration like a mini wedding and I did buy a regular dress but being 20weeks pregnant it just doesn’t fit right even with adding a corset.

I found a dress that is maternity that will stretch and fit better but I’m self conscious of my arms since I gained weight and have some stretch marks. and they didn’t have any long sleeve ones so I want a pretty flowy cardigan to go with it should I do a lace cardigan? Or a knit cardigan?