Discord has also been using ancient electron versions for a long while now (I don’t know if they’ve since updated to versions that haven’t been EoL’ed).
On Linux, I literally have a better experience using discord in my browser than the electron version.
Edit: looks like discord updated to Electron 22 in March 2023, with the update to Electron 23 happening maybe at the end of the year or early next year, according to this reddit post. So they’re getting better, but still a bit behind.