All mail sent to gmail suddenly now bounces back with SPF problem 2/13/23

All mail to gmail addresses bounces back as undeliverable with Error code 550 - 5.7.26

I found and added the SPF record at my registrar. Not working yet but may still need to propagate.

Do I need to add a DKIM record too? If so, how? Instructions in this forum are 6 years old and no longer valid. Can't find how to do that anywhere.