The answer is yes, an ssl cert has been marked as a ranking signal by Google since 2014.
Moreover, some web browsers like Google Chrome and Firefox have marked a non-ssl(HTTP) site as insecure, which can be seen from the browsers left side of top navigation bar. Imagining how people will think about the insecure sign when browsing your site.
You should add an SSL cert to you site if you really concerns that. Since you want to do it without cPanel. I would list the most used free and paid SSL certs on the block and direct you to the easiest guides(free tools). Here you go:
- Let’s Encrypt.(the most used free SSL cert)
- Namecheap and RapidSSL(the most used paid SSL cert)
Hope this helps!