list of ways to use a desktop-based version of Facebook Messenger

methods that are maintained by Facebook itself:

• access messenger.com using any browser
• download the Windows-native Messenger app (requires Windows 10)

methods that are maintained by a third party:

• the Opera browser actually has Messenger built-in from the factory [2] [3]
• Chrome apps (note that Google ended support for Chrome Apps as of June 2022)
  • "App for Messenger", by Jorvi, last updated 2018
• Firefox apps
  • "App for Messenger", by Fernika, last updated 2018