Maximilian L. dang 2 years ago is like 100 in tech years. Really really tough spot. Listen, I have nothing personal to gain from convincing you to start from scratch, I'm speaking from experience. I currently sit in the same seat you do with one of my freelance clients - I've been with them for over 8 years now - and I've redesigned their website each and every time.
For me, it was easy to convince the stakeholders to start over because I knew how much more valuable it would be to use the latest in AI content generation, the latest Relume tools, and the latest and greatest foundational pieces (client-first), and most importantly, be able to apply any new learnings to an even better, more organized website that was built better than before.
Let's take a look at this from a different perspective.
Its been two years since the website was redesigned.
If you don't start over this year (this time) with the marketing site - you will eventually - so you're just delaying the inevitable right?
2 years ago, we didn't have components with figma or webflow variables. So now you are stuck with our v1.5 version of components.
Which means you would not be able to use our Webflow app to bulk import pages/components at all - its literally not possible to use our webflow app with an older style guide - it has to be a 3.0 style guide. There's no technical way around this unless Webflow introduces new APIs for us to be able to do this (doubtful).
I would bet starting over, and being able to use the style guide builder, design tab, and the webflow app would more than make up for the lost time and potential hassle of starting over.
There's a lot of things I don't know about your marketing site though - like how many CMS collections, or redirects, or how much money has been invested in SEO or in paid marketing. Certainly all of those things compound into the decision to not start from scratch.
If starting from scratch is not an option today (which by the way, if any of the reasons above are why you are not, those things will only compound even more, 2 years from now...just saying) - then I would say your best bet and workflow for this would be to generate wireframes and manage updated content directly in Relume and then you would just simply copy/paste components from Relume into Webflow. That's really your only option actually. Then you'll be styling those components in Webflow as well.
I would assume that you could start a new Figma file though, at the very least you could turn your current figma file into a library to then reference color styles, fonts, logos, assets, components etc from that current file, into a new figma kit - and if thats the case, you would actually be able to take advantage of the full set of tools from Relume in Figma.
Its just when it comes time to build in webflow, you'll only be able to import manually, page by page, the wireframes and then you'd have to "old school" reference your figma file to implement the designs in Webflow. For me personally, that's a fun process anyway.
Hope this context/perspective is helpful - best of luck! 🚀