Teams has switched to Microsoft's own edition of the same concept, "Edge WebView2". Now that Edge is just being Chrome wearing a rubber Scooby Doo mask, I don't expect the differences are vast.
Another fun iteration is Plex's desktop client, which uses QtWebEngine... however surprise! still the Chromium engine underneath.
Signal's desktop app is plain old Electron though.
Of the ones on your list, worth noting that Discord and Slack work fine with FirefoxPWA.
It's also quite common for updates to be sent using a ceiling-mounted infrared transmitter, like this brand which is common where I am:
https://www.pricer.com/products/devices/electronic-shelf-labels
People have figured out the data formatting to update some of the lower-security variants (including that "Pricer" brand):
http://furrtek.free.fr/index.php?a=esl