Will using a CDN have negative impact on my SEO?

There is a common misconception that using a CDN always has a negative SEO impact. It's not true.

In the tutorial I showed you how to use Cloudflare. Cloudflare is a reverse proxy so your website URLs remain unchanged (very important). They stay exactly the same as if you used no CDN at all.

When using other CDNs, you need to make sure that proper URL structure is setup, otherwise you may get some negative consequences SEO wise, especially if you're relying on image search for traffic. It does not happen automatically. How this needs to be done is explained very clearly in this article from Inflow:

Four SEO Best Practices for Using a Content Delivery Network (CDN)