I didn't find any good options for mounting my camera to a metal structure in the garden, so I made one. Works well as long as it doesn't get too hot for your filament. I mounted one of these on a gutter and the PLA folded up due to getting soft and CTE difference between plastic and metal. When mounted on a bulkier high mass surface it has worked great.
Link for the magnets that I used below. You'll need to to glue them in with superglue, and you'll need 10x of them.
Original model link shared below in case you need to modify.
Magnets (Qty 10)
https://www.apexmagnets.com/magnets/1-2-x-1-8-disc-rubber-coated-neodymium-magnet
Threaded inserts (M3x3, Qty 3):
https://cnckitchen.store/products/heat-set-insert-m3-x-3-short-version-100-pieces
The author marked this model as their own original creation.