Is it possible to point a subdomain to a different hosting provider, while keeping the main domain on our current hosting platform?

Absolutely, it's a common practice to point a subdomain to a different hosting provider while keeping the main domain on your current hosting platform. This is known as a "split DNS" setup. You can achieve this by updating the DNS records for the subdomain at your registrar or DNS provider, pointing it to the new hosting provider's nameservers.
Meanwhile, the main domain remains unaffected, continuing to resolve to your current hosting platform. This setup allows you to take advantage of specialized services or features offered by the new hosting provider, such as improved scalability or security, while maintaining control over your main domain.

When setting up a subdomain, you'll need to configure the DNS by provisioning an A-record that maps to the IP address of your server or, alternatively, delegate the subdomain to your hosting provider's nameservers (NS-records) for further management.
On the hosting side, create a new subdomain entry and associate it with the desired website, ensuring a seamless resolution process. This setup will enable your subdomain to resolve correctly, allowing users to access your site without any hiccups.

Provisioning of DNS records can take anywhere from a few hours to several days, contingent upon the registrar's processing timeframes. Moreover, the activation of an A-record may not be instantaneous, as it is subject to the propagation time of the DNS cache.

It's essential to note that numerous DNS service providers necessitate the creation of a second-level domain prior to adding a third-level domain and associated website. This requirement holds true even if the second-level domain and its corresponding website are hosted on a separate DNS hosting platform.

When configuring DNS delegation, it's crucial to specify a minimum of two NS records with disparate values, namely the DNS server names. For instance:

subdomain IN NS ns1.estic.com. 21600

subdomain IN NS ns2.estic.com. 21600

In this example, the TTL (Time-To-Live) value is set to 21600 seconds, which is a configurable parameter that determines the cache expiration time for DNS records. This value can be adjusted according to specific requirements.