Seeking Advice on Redesigning Webflow Site Using RELUME Components

Hi everyone, I used to have my site made by a service provider who adopted the client first structure (from 2 years ago). Now I want to do a COMPLETE overhaul of the site. I want to do the new one with RELUME components. However, I want to stay in the same Webflow Project because I have a lot of CMS data that I want to keep. Do you know how I should proceed ? - Do I delete all the guide styles, and all the classes, all the pages and properties I've created? - Or is it better to create new classes ? I was thinking about erasing almost everything except the CMS, work on a new style guide, new classes + published once the new website is ready. I'm lost and I'd like your advice on this. Thank you very much