Hello Noah Wallach,
Thanks for using Apple Support Communities. It's our understanding that some of your outbound calls don't appear on the Recents list on your iPhone 12 Pro Max. We're here to help.
There are no settings that you need to change in order for the calls to appear in the Recents list. We recommend that you make sure that your carrier settings are up to date and restart your iPhone. Restarting can resolve many unexpected behaviors.
Manually update carrier settings on your iPhone or iPad
Restart your iPhone
Let us know the results. Does the issue occur with inbound calls as well? Please include any other troubleshooting steps that you may have tried
Have a nice day!