Use Mimestream. It's wonderful and GMail-backend-only fully native Mac App by one of the former lead engineers of the Apple Mail app.
$50/year? GTFO
What would that get you over just the chrome version?
It's much worse. It is difficult to customize a native app, but browser apps are easy to modify with extensions, even easier with coding agents. If I have to use a proprietary app, a web app is least objectionable.
It would be much snappier, and would trivially support common native features like being able to open messages in new windows.