I did read the article and reviewing it again and searching for "react," "progressive," and "pwa" returns zero results.
I think the article opens by stating a pretty strong disadvantage:
Flutter apps run as Android apps and so are less "native" than something like a PWA or react app, which would just run in the browser.
The article doesn't address my concern at all and I was hoping to have some constructive feedback about that concern, which did not happen.