Hopefully Plex can figure out why the app is incompatible and address the issue.
An alternative to Kodi is an Amazon FireTV 4K or Roku Premiere. They are currently on sale for $30 - $35 USD. If you could repurpose it to another TV it would not totally be “throw away money” if/when the Plex app is available for your TV.
Depending on your level of adventurousness, you could try side-loading the Plex app to your TV. Google “side load Android TV,” “side load Sony Android TV,” or similar. You can download the APK from the announcement thread.
