An outlook in the near future: We're working on adding Tabbed Application Mode 📑 to PWAs, so you can, for example, edit more than one document per window.
@tomayac's latest article has all the details you need to know about this Project Fugu 🐡 feature.
https://web.dev/tabbed-application-mode/

https://twitter.com/ChromiumDev/status/1364987130058006535