Seeking advice on transitioning a site to back to client - How do you manage design integrity?

This is more a client management/business related question for designers who create websites on behalf of their clients. I’m wondering if other designers have any tips on how they handle the transition of a customized website back to a client. Wix is amazing for building customized design from scratch in a user-friendly way but I have found layouts to be glitchy for some reason when elements are edited. If one is not careful or experienced with Wix, large blank spaces can appear on the section background or other elements get shifted (that’s a topic for another day…).

What I’m trying to achieve is a client management process that still allows clients ownership/agency over their site but where the integrity of the design can remain intact through their content edits to protect their brand image and the functionality of the website. Do folks tend to add in an ongoing oversight/maintenance clause/cost into the initial design contracts? Or do you just wash your hands of any design flaws after the website is launched and avoid promoting the creation of the site in your portfolio if the website design falls apart?