GDrive: Token has been expired or revoked

I gather that this thread is what the issue is here.

It has to do with the new GDrive “enhanced security”.

Unfortunately, that thread points to newly-updated instructions for making your own client ID.

What if I’ve already got a client ID? Could someone possibly walk me through the steps to get my existing ID to work with the new security?

Or, if I have to set up a new ID, could someone walk me through doing that without losing access to my encrypted shares.

I’d be most appreciative and I’m sure I’m not alone in being perplexed (and fearful!) about how to proceed in this case.

Thanks in advance,