I don’t personally see any issue with this split, since here is a distinct change in the members and name at the same time. could also use this new relationship to connect the two~
looking at their artist page, there are several URLs for both The Jackson 5 and The Jacksons, and they’re also separate in several other databases, including Allmusic, Discord, and RateYourMusic
edit: while browsing their artist credits, I just found this release that also specifies it’s both The Jacksons and The Jackson 5 (this does seem to be the only case they’re both credited on a release tho)