I have tried using java that is not bundled with MC, and also did a manual update on my network card, still getting the error, as of 1.16.
Little update, I CAN connect to Realms via Bedrock, but still not at all through Java.
No idea if that will help at all, but that is an update.
I was sent here by them, after they helped me try all that above. None of which resolved any of said issue.
So, OP here for this issue.
I have found a fix, but it is honestly annoying.
Complete Clean Reinstall of Windows.
I still do not know what may have caused the issue overall, but having done this, it is no longer an issue for me.
Though, I would wish for this thread to stay open, as a clean install should not be the only fix for this issue.