Conversion from Divi 4

Hi Mak,
I'm loving Divi 5 and they way it encourages us to start the design process in a more professional way. The tools, courses and advice that you're providing are absolutely superb, and I've been making the most of these on my new website projects.
However, I have a considerable portfolio of Divi 4 websites and I would very much appreciate you suggestions on best practice for migrating these sites from Divi 4 to Divi 5. Wherever possible, I'm trying to incorporate variables, presets, etc. but I feel what I'm doing is a bit hit and miss. I would love to follow a comprehensive methodology for this process. Is this something you might consider creating.