Best diaper cream

Baby has his first diaper rash at 6 months. He's on steroids and motrin and tylenol for a bad case of croup going on day 7. I've also tried to go diaper less but it's hard when he's so sick and fussy already. Laundry to keep up with him peeing on everything is exhausting on top of a baby that won't sleep and is sick.

Brands we've tried

Aquaphor

A & D

Butt Paste

Desitine

I've also tried a couple of combos like

A & D + Butt Paste

Aquaphor + Butt Paste

A & D + Desitine

At what point do I take him back to the doctor again this time for a diaper rash?