The reply begins with the word "Yes" but the remainder of the words are complete nonsense which leads me to question whether "Yes" can be trusted.

I see many many questions about how to properly configured your SPF record to allow successful sending of invoice emails with Quickbooks Online but no one from Intuit has been able to provide a workable answer.

For the record, a list of dozens of IP addresses or host names that could change at any time without notice is not a workable answer. A properly formatted SPF record is a workable answer.