Self help domain mapping without access to cpanel

I am trying to create a client hosting website where I will host all my clients' website using Multisite. As such, I will need to perform a domain mapping to their TLDs or a sub domain.

From the Domain Mapping user guide, it states that we will have to add a A Record / CNAME for mapping of domains to TLDs and sub domain mapping.

Would like to understand if there are ways to bypass this part or do it via PHP? In future, I may allow subscribers to self develop their website and map to their own domain like Wordpress.com. However, I do not wish to grant them access to my cpanel.

Thank you in advance for the assistance.