Sounds like a smart approach using your script with Figma variables. There’s no ready-made tool to convert Webflow styles directly into Tailwind yet. Starting with Vercel, Next.js, Supabase, and Tailwind is a great stack.
As for a base repo combining all that with Relume, nothing widely available, but most people build their own and add Relume components manually. You can check Relume’s community or GitHub for starter kits.