Hello TDevereux.
Thank you for using Apple Support Communities. It sounds like you're not receiving notifications for Apple Cash transactions, even though you have this feature enabled. We can understand how this would be an issue. Allow us to investigate this issue and assist in any way we can. We also notice that you're coming from a great resource below:
View and limit your child or teen's Apple Cash activity - Apple Support
Just so we can better understand your issue, we’d like to ask a couple questions. Do all your other notifications work without any issues? If you switch to your cellular network, do notifications for this specific feature start to populate? If you do have any pending updates, it would be best to install them to help isolate this issue. Just in case, the resources below can guide you:
How to back up your iPhone, iPad, and iPod touch - Apple Support
Update your iPhone, iPad, or iPod touch - Apple Support
Keeping your device fully updated can help resolve various issues and also with overall performance. If you're already fully updated, you can attempt the following troubleshooting steps. Temporarily turn off the "Makes Any Transaction" feature. Then go to Settings > Notifications > Wallet. Turn off "Allow Notifications". Then go ahead and restart your iPhone.
Restart your iPhone - Apple Support
After it restarts, go ahead and enable both notification settings for the Wallet app and the "Makes Any Transaction" option. Feel free to keep us posted on your results. Cheers.