Came here to say most of this, also worth calling out the note at the bottom:

> Note: This research was presented as an abstract at the ACS Clinical Congress Scientific Forum. Research abstracts presented at the ACS Clinical Congress Scientific Forum are reviewed and selected by a program committee but are not yet peer reviewed.

My guess is when it gets to peer review, one of the reviewers will request at least mentioning these limitations. As it was only an abstract, it’s possible the paper itself does mention these limitations already as well.