Setting local static IP and SIP ALG

Good afternoon, community!
I've been using Xfinity for a bit now, and have questions on how to configure a couple things.

How do I disable the setting SIP ALG?

How can I set a static IP for a local device, such as a homelab server or printer?

I have admin access to our Xfinity router's web interface and mobile app. A point in the right direction to these settings would be great.

Thanks, all!