Facebook Messenger on desktop keeps quitting whenever I open it, what do?

[Kankurette]

For reference, I have a Mac that I got in 2016 when my house was burgled, so I'm guessing it's a bit clapped out now. I'm not on Facebook anymore as I deleted it back in 2020 but I still have Messenger on my Mac and phone.

Messenger works fine on my phone but the desktop version is really buggy. I've tried deleting and reinstalling it countless times and deleted the password in my keychain, but the fucking thing quits as soon as I open it. One time, it did work but all the conversations from January onwards were deleted and new messages weren't showing up. Is this normal for Messenger or is my computer just shit?

[Endicott]

I'd guess it needs updating, but why use a desktop app when you could use it in a browser?

[Kankurette]

Don't you have to be on Facebook to use it in a browser?

ETA: apparently not.