According to the Manual, it is possible to
Select “Mark and Lap” to trigger the lap counter at a specific GPS location marked before the ride and at any location during the ride where you press the Lap-Button
https://www8.garmin.com/manuals/webhelp/GUID-16B12CFE-F96E-4DE9-9F5F-8C4A5936D3B9/EN-US/GUID-24EB7772-9FBE-448F-842B-799CF200895E.html
How can I create these “lap positions saved in the course”? I was looking into the course points, but nothing looks like a lap position in there.
I am able to Mark the current position of the device in the lap menu, but that is not really helpful when planning a course where I want to create pre-made laps.