Hi, john!
Actually all the bugs in page loading do have the same nature: the old engine non-supporting ECMAscript 6 standard (latest javascript version) in full.
You can freely transfer your logins into PaleMoon (NewMoon, MyPal) or Basilisk (Centaury, Vasilisque) or any other UXP-based browser: Borealis, IceapeUXP etc.
First you can try to simply copy files
key4.db and
logins.json from your k-meleon profile folder to the your other Goanna browser profile (when that browser is closed).
NB!!! This will overwrite all login data of your other browser with data from K-Meleon.
More correct way is to use
Password Backup Tool extension. Install it into K-Meleon (the same way as in PaleMoon) and in your other Goanna-based browser. Export logins from KM and then import in your other browser. Voila!
P.S. New Firefox Quantum also accepts
key4.db and
logins.json as the store for login data. Feel free to try simple file transfer to the fresh Firefox profile!