MX records mailgun and gsuite /gmail. Using a subdomain on mailgun = Adding a subdomain on my WP hoster (siteground)?
I use Mailgun for several domains that also have email associated with the domain. The key is to set up Mailgun using a subdomain as you did.
You will need to add the MX records to your DNS. Since you should set those up with the host as your subdomain, then these should not interfere with your email setup.
Here is an example of how those records should look when added to Google domains. Note that the host is set to be mg which is the subdomain in this case. In your case, this would be mail.
