re: Fiber rich foods for toddlers/young children

My toddler has occasional issues and we use miralax once/twice every few weeks, so it's not bad enough for us now that we've consulted her pediatrician beyond miralax.

Ive started looking into probiotics. There's a Tropicana juice blend with probiotics (doesn't help OP). There are also vitamins with probiotics. Unsure if this would be helpful or if there's no real effect. Any adults here use probiotics with success?