Correct, we cannot assist, changing the nameservers is not possible.
With this we cannot assist, but we can suggest and test. These records may have been imported when you added the site (domain/zone) to cloudflare. The site loads fine for me, is it not as you expected and/or is it out of date?
On the namecheap side they tell me that ALL the DNS records of the namecheap hosting cPanel must be pointed from the Cloudflare DNS, but I see that this is not possible, what could I do? I leave the message here:
“In order to connect the domain pointed to Cloudflare DNS to Namecheap hosting it is required to copy all the DNS records from Namecheap cPanel and create them on the Cloudflare side.”