The AtomRC Dolphin motor mount is pretty weak, and barely glued in. This mount replaces the stock wooden one, with an insertable mount. There is an included 19x19mm plate which attaches via m3 bolts and screws into nuts on the mount.
Best to print with Nylon - I use PA6-GF with 5 walls, 5 top & bottom layers, and 25% honeycomb infill. If you can't do nylon then ASA/ABS, and if you can not print those, get a better printer ;) jk PETG will be fine too but I found that PETG tends to crack and split with parts with numerous holes that are subject to stress.
The author marked this model as their own original creation.