I have not found a way to do this, but you might check with support, I do recall seeing a 301 hack that allowed the opposite to happen ( redirecting the homepage only ).
You have a couple of options here. The main one I’d recommend is to just load in your 1500 redirects. Not Ideal, I know, but it’s the best-aligned approach with Webflow’s design.
You can prep them all in a spreadsheet, export as CSV and bulk-import.
Another possibility is to use your 404 page for this purpose and add a redirect script there, however I’d be concerned about SEO damage as the 404 would be the first response that googlebot sees. It won’t delist it, but I wouldn’t be surprised if those links take a pagerank hit.
Another possibility is a reverse proxy. Can be complex and fragile to setup properly, but gives you full URL control once you have it.