Singles tag guys almost always lose to higher level single wrestlers in one on one matches though… look how many time Dax lost singles matches as champ. Chelsea is a midcard talent and that’s for the most part what tag teams are is midcard talents either in their way up or back down or just relegated as tag team specialists
fwiw I hated Dax losing single matches when champ but I don't disagree its ok once in a while. the main issue for the women is that they very rarely have long stories or feuds with other tag teams and were used as fodder for single stars.
fwiw I agree in principle it's especially not really a big deal for Chelsea since as you said, she's been slotted as a midcarder in singles competition.
in either case I was mostly just relaying one of the reasons they originally left, if I'm being honest, the tag division was likely just a small drop in how they felt treated in general at the time of their departure.