Hello eigsin,
Welcome to the Microsoft Community! It's my honour to be able to assist you.
I understand that you are having problems downloading files on OneDrive and that OneDrive is not working, so feel free to let me know if I'm misunderstanding you.
In order to help you better, I would like to know more about it:
Can you log in to OneDrive? We suggest you try to log in to the web version of OneDrive first to see if it's a problem with your account. Login link: onedrive.live.com
Are you getting any error messages when downloading files? Can you take a screenshot and share it with me?
According to your description, I understand that you have tried some troubleshooting solutions. This will avoid giving you some duplicate solutions.
If you can't start OneDrive, you can refer to the following article to try to fix it: OneDrive won't start - Microsoft Support
If you are able to log in to your account, you can download files to your device by referring to the following article:
Download files from OneDrive to your device - Microsoft Support
We look forward to hearing from you. Please feel free to let me know if you have any other updates, thanks.
Best regards
Isabella-MSFT | Microsoft Community Support Specialist