Return it. These cheap import motors can have very, very poor quality control.

You may have more luck getting a surplus/aftermarket motor from a vehicle's power seat or power window on ebay. Some of those on Amazon as well, but usually cost more on Amazon. One like https://www.amazon.com/12Vdc-Right-Angle-Drive-Electric/dp/B005IR1NBA/ref=sr_1_8?dchild=1&keywords=power+seat+motor&qid=1600152960&sr=8-8 may be good, but I can't vouch for any in particular. That doesn't look like it's actually vehicle-quality, but meh it'll do.