Creating a Subdomain for a root domain that is not hosted at SS

We have our root domain hosted with a third part.

https://www.whois.com/whois/sustainableneighborhoodnetwork.org

I want to create a subdomain for SS pages, to get more design control that what our root domain can provide.  

Can I create a subdomain with SS if the root domain is hosted elsewhere?  If yes, is there a help article?

If not, can I point SS to a subdomain hosted by a third party that is not one of the major domain hosts like GoDaddy?  I found instructions on connecting to a third party for a subdomain but my provider was not on the list.

If I do connect to a third party of any sort, am I inviting page load performance issues?

Thanks!

10 minutes ago, JTW said:

 

I want to create a subdomain for SS pages, to get more design control that what our root domain can provide.  

If you require a subdomain, you must create this wherever the root domain is hosted. 

However, can you explain what you mean by getting more design control?

Thank you for your response.

Design control relates to the CMS we are using for our root domain, which is Sitefinity.  Sitefinity is very dated and does not allow for the layout or creative options that SS supports.