https://www.techradar.com/news/google-photos-is-now-available-as-a-desktop-app-sort-of

Good news for shutterbugs – Google Photos is now available as a Progressive Web App (PWA), meaning you can add it to your desktop or your phone's home screen. Provided you have Chrome installed on your device, the PWA will run like any native app, without the need to open the browser.

To add the new Google Photos PWA to your desktop, visit the Google Photos site in Chrome, click the menu button on the top right, go to 'More tools' and select 'Install Google Photos'. If you can't see that option, you'll need to visit chrome://flags, search for 'Enable app banners', choose 'Enable' from the drop-down menu and then restart your browser.