Toddler in the Pram, baby in the sling. Or toddler and baby in sling. Or both in the very big pram and the Aldi shopping as well. All works. Just an ordinary sling. Not the fancy ones. The ones you tie yourself with knots. Easier to wash, no problems with growth and easier to store.
I’d also put baby in sling wrap (you could also use for toddler at other times) and also maybe a buggy board which clips to back of single buggy. These fasten up when not in use. If you buy a wrap sling and buggy board with a single plan than you’ve got flexibility.