If you are looking for an open source alternative to Webflow, then Webstudio might be of interest to you. Their newest product update allows you to copy and paste elements from Webflow component libraries and paste them directly into Webstudio while retaining styling and formatting.

Interestingly it translates Webflow styles into design tokens and allows you to then use the components natively inside of Webstudio.

There are some limitations for what elements are supported. Learn more about those here.