I think replacing it is the way to go. It's important to differentiate between the acute symptoms of COVID and the chronic, persistent long-term symptoms, even if they both emanate from the effects of the SARS-CoV-2 virus on the body. It will be helpful for research, treatment, and the general understanding of physicians, mental health practitioners in the general public.

I think there's precedent for such a decision in how concussions are generally viewed. An individual can be diagnosed with a concussion, which has common, acute symptoms. If the acute symptoms last longer than is typical for a concussion of a given severity, the individual could be diagnosed with persistent post-concussive symptoms (a.k.a. post-concussion syndrome). Of course brain injuries are different than viral infections, and we still have a ton to learn about brain injuries, but it's the idea of clearly differentiating between the acute effects and the chronic, persistent long-term effects.

To be clear, I'm not trying to relate COVID with concussions beyond the medical nomenclature, but I think the nomenclature is effective in making the distinction to which I'm referring. It's not perfect, but we'll never have perfection in research.

Edit: It's unclear if the paragraph breaks are displaying properly, so I apologize if it appears as a wall of text.