Hi,
was a while back since I did this but finally solved it this way (if I remember correctly):

The settings are stored in this file: ~/Library/Application/Support/com.apple.sharedfilelist/com.apple.LSSharedFileList.FavoriteServers.sfl2

So, simply add the servers manually in Finder as you usually would do. Then create a .DMG using composer to add this file in the users folder. Upload this to JAMF and choose Fill User Templates and Fill Existing User Home Directories in the policy.

And, also you need a script to get it working afterwards. In this case we simply use the full IP-address including SMB (which I don't think is necessary), if you want a more user friendly name you'll need to change that in the script.

#!/bin/bash

USER=$(/bin/ls -l /dev/console | /usr/bin/awk '{print $3}')
plist=/Users/$USER/Library/Preferences/com.apple.sidebarlists.plist

servers=(
'smb://192.168.0.10'
)

killall cfprefsd
echo "Setting servers for $plist"

#Add favouriteservers
echo "Creating new list..."
/usr/libexec/PlistBuddy -c 'add favoriteservers:CustomListItems array' "${USER}"/Library/Preferences/com.apple.sidebarlists.plist
/usr/libexec/PlistBuddy -c 'add favoriteservers:Controller string "CustomListItems"' "${USER}"/Library/Preferences/com.apple.sidebarlists.plist

for i in "${!servers[@]}"
do
    echo "Adding to Favorite Servers: ${servers[$i]}..."
    /usr/libexec/Plistbuddy -c "Add favoriteservers:CustomListItems:$i:Name string ${servers[$i]}" ${plist}
    /usr/libexec/Plistbuddy -c "Add favoriteservers:CustomListItems:$i:URL string ${servers[$i]}" ${plist}
done

echo "Finalizing settings..."

killall cfprefsd

#kill sharedfilelistd process to reload file. Finder should be closed when this happens
killall sharedfilelistd

defaults read ${plist} favoriteservers > /dev/null

Hope this helps!

Does this still work?  Anyone know?

Hey @KSibley, I can confirm this method works as of today 10/3/22.