This is incorrect advice. Make does not send the actual email.
Make logs into your email server using the established connection credentials, and then your email server sends the emails out.
Therefore, including make.com or Make IP addresses in the SPF records wouldn’t have helped.
For more information, see this duplicate question: Help me understanding SPF signature please!
Hope this helps! Let me know if there are any further questions or issues.
— @samliew
P.S.: Investing some effort into the Make Academy will save you lots of time and frustration using Make.