@Fiera24, the practitioner listings wouldn't "weigh down" the organization's GMB page in terms of making it less likely to rank well.
The main concern is category overlap. If you really don't want the org page to be third banana to one or more practitioner pages, then the practitioner page(s) should use GMB categories different from the org's category.
That's somewhat related to the (smaller) concern of where Google reviews should go. If you want to ensure that all Google reviews go to the org page, you may want to skip the practitioner page(s).
That's good to know, thank you! On a similar, but different note, what about org locations that are somewhat near each other (5 miles apart). Should they have different primary categories as well? Thanks!