I remixed the mounting bracket to fit a CQRobot 70:1 metal DC geared-down motor https://www.amazon.de/dp/B08ZK8NV4Q.

It has enough torque to handle a full 1kg filament spool, but the mount needed to be stiffer. As I had problems fitting the gear properly, I made it a rather tight interference fit. Depending on your print result, you might need some post processing or heat-set the part.

The bracket showed a distinct tendency for warping at the thinner end if printed with more than 2 walls/0.4 nozzle, so I'm still a bit wary about the profile. I changed a few things, switched to a smooth plate and now it works fine for me. Any suggestions are appreciated.

The push pins of the pastamatic can't accomodate for the lateral forces though and will shake lose over time. You'll need some other method of mounting.

Update:

The gear of the motor was a bit too far away from it's counterpart. I reduced the length of the bracket, and now the mating of the gears is considerably improved, resulting in lower noise, smoother operation and reduced load on the motor. Sorry for the inconvenience.

Specs of the motor according to amazon:

• 6V or 12V 70:1 Metal DC Geared-Down Motor 37Dx54.8L mm, with Metal Mounting Bracket Kit, D-shaped Output Shaft 6mm Diameter and Long 16mm;
• Max Power: @ 6V: 5 W, @ 12V: 10 W;
• No-load Speed: @ 6V: 75 RPM, @ 12V: 150 RPM;
• Stall Torque: @ 6V: 15 kg.cm (202 oz.in), @ 12V: 27 kg.cm (380 oz.in);