PROND Swing Swivel 35kN Safest Rotational Device, Swing Spinner, Carabiner Swivel, Climbing Rope Swivels for Children’s Web Tree Swing Setting, Aerial Dance, Hanging Hammock

In terms of the eyelets: The nice thing about rope is you can just tie knots although 3mm is probably too small to get a stopper knot I recommend you buy one of these: https://www.amazon.com/dp/B08MVS782V Tie a bowline to one end (look up the knot). The other alternative is splicing or sewing to make an eyelet.