How to lock my kids out of Mail on their Mac

I have set up my kids (5 and 9) with an older MacBook Air (Intel but running Sonoma) connected to a monitor and keyboard (so more or less like and iMac) for school work.

We use Screen Time and JAMF Now to manage the computer.

I would like to lock the kids out of Mail.app for the time being and I can't seem to figure out how. You can do this for iOS in Screen Time but not MacOS. I attempted use MacOS permissions to apply and ACL but because it's a system app SIP won't let me change it.

This seem like it would be simple to do and I have even seen screen gabs of older versions of the Parental Controls that let you lock apps out but this Screen Time doesn't seem to support it. JAMF Now doesn't seem to ether you have to use JAMF Pro.

I've been a Mac system admin for 20 years but am somewhat new to parental controls... any help would be appreciated. Thanks!