How to use variable in path

I need to disable ipv6 on the network interface config file. The interface name is not the same for all environments. How I can achieve that ?
playbook :

Just replace {{ item }} with {{ ansible_default_ipv4.interface }} and delete the loop

It worked Matt!
Ironically I did try that but it was gather_fact = false and it failed previously.
Thank you !

Regards,
Sanjay C.