3 ways to loop a video fragment in Davinci Resolve:
1. Place the playhead after the clip, elect the required clip on the timeline and press F9.The fragments will start to copy after the playhead.
2. Speed up copy-and-paste process by holding ALT and moving the desired clip on the timeline to create a copy, Select multiple copies and drag them with ALT pressed to increase productivity.
3. Place a Fusion Composition on the timeline, drag it to the required length, go to Fusion, drag the clip from the Media Pool, click on it and check Loop in the mediaIN prodertis. Connect it to the node in Fusion. NB: If you enlarge the Fusion composition after that, the looping will stop at the original end. So first enlarge the Fusion Comp, and then add the media.