Yeah doesn't help that when you google "technical issue ffxiv launcher" all the guides from third parties say the last resort is to reinstall. We had this issue once before after a patch and a reinstall did fix it, so I assumed it was the same deal. I only thought to go to social media to check if anyone else had this issue after not being able to fix it with a clean install. Def know for the future now and will check here first, hah. Hopefully some of those other sites update their articles to mention it can be a their-side issue and not just your computer.
Having an official statement from Square when they're aware this is happening would be really nice, at minimum, so we don't spend ages troubleshooting.