I would be less worried about your cat opening your email then sending a message to your client and more so on the security and privacy implications of continuing to use proprietary services provided by FAAMG.
Learned how to build a website from scratch just recently with basic HTML and CSS. It honestly isn't that bad, just a matter of finding a way of presenting it in a way that is easy to understand and retain.
If a retard like me can do it, then I don't doubt you can too.