Updated 07102022-150539
I know it's not what you asked about, but I DID find this document. https://support.google.com/docs/answer/179738?hl=en&co=GENIE.Platform%3DiOS
https://www.icloud.com/numbers/0aciZ1WgCI6KdYu8F8hf-cZ6g#Google_Docs_for_iOS/iPadOS_Keyboard_Shortcuts