for reference, I managed to create a "nopgk" package to do so and change the setting `AggressiveUpdateNotificationDays` to `90` in my case.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "
http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>OnDemand</key>
<false/>
<key>_metadata</key>
<dict>
<key>creation_date</key>
<date>2022-12-08T12:10:44Z</date>
<key>munki_version</key>
<string>6.0.1.4523</string>
<key>os_version</key>
<string>13.0.1</string>
</dict>
<key>autoremove</key>
<false/>
<key>catalogs</key>
<array>
<string>testing</string>
<string>production</string>
</array>
<key>display_name</key>
<string>Munki Relax aggressive updates</string>
<key>installcheck_script</key>
<string>#!/bin/bash
if [ "$(/usr/bin/defaults read /Library/Preferences/ManagedInstalls AggressiveUpdateNotificationDays)" = "90" ]; then
exit 1
else
exit 0
fi</string>
<key>installer_type</key>
<string>nopkg</string>
<key>minimum_os_version</key>
<string>10.10.0</string>
<key>name</key>
<string>MunkiRelaxAggressiveUpdates</string>
<key>postinstall_script</key>
<string>#!/bin/bash
/usr/bin/defaults write /Library/Preferences/ManagedInstalls AggressiveUpdateNotificationDays -int 90
</string>
<key>unattended_install</key>
<true/>
<key>version</key>
<string>1.4</string>
</dict>
</plist>
This can be used to change all settings, so guess I'm fine now.