One Canva Design, a Whole Social Kit
Design once at the largest size, resize everywhere, and leave room so the resize doesn't clip the message.
I used to rebuild the same post for every platform. Now I design once in Canva at the largest size, then use resize to push it to every format, fixing only the bits that break.
The trick is leaving room. A design packed to the edges on a square looks cramped on a story. I keep the important part centered with negative space so the resize doesn't clip the message.
I save the resized versions as a brand template so next month's post inherits the layout. The kit isn't one file, it's the set plus the template that regenerates it.
Canva's background remover and a consistent font do most of the branding work. The kit looks intentional because the constraints are fixed, not because I redrew anything.