Webflow hosting isn’t designed for that, although there is apparently an enhanced [ pricey ] level of CMS scaling available with Enterprise plans.
First I’d check for some of the vetted workarounds.
If you don’t find what you need there, you have some options;
HOST ELSEWHERE
Export your whole site, and host it elsewhere.
Here you’d need to fully replace the CMS with a database / headless CMS solution.
PARTIALLY HOST ELSEWHERE
Same as above, but just the pages needed for, e.g. your 100,000 articles.
You can set that sub-site up on a subdomain, e.g. news.mysite.com
If you want, you can setup redirects, e.g. /news/(.*) → https://news.mysite.com/%1
If you really want, you can setup a reverse proxy ( a fair bit of work ) so that different URL requests are routed to different servers, transparently.
You’d have to research the best SEO setup for that, and of course you’d be generating your own /sitemap.xml.
Google would probably consider them to be two separate sites however the new GSC feature for domain validation might change how it handles and processes properties like this that spread across subdomains.