From your second image, these records:
need to be set as the domain's nameservers, not added as DNS entries (it's confusing, I know :/).
To do this click on "Transfer DNS to Webhost"
and add those two cloudflare nameservers from above on that page
NOTE: When you do this the DNS settings you have set in the namecheap control panel are no longer active, the DNS records for your domain are now controlled by cloudflare (that is what setting the nameservers for a domain does).
Then, go to the cloudflare settings page and click on the DNS tab. You will add the webflow dns records that previously would have been on namecheap on a page looking like this:
Let me know if you have any other questions or if that didn't solve your issue!