Technically this would be possible, but I would not recommend it due to the complexity and performance issues you will encounter. You would need your server to proxy requests from /blog and its subroutes to the webflow hosted blog.
If you really want your blog to be hosted on Webflow, you could put it on a subdomain like blog.domain.com, although this might negatively impact SEO performance because from what I know your blog and website would be ranked separately.
Maybe it’s not the answer you were hoping for, but good luck anyways