What to do with these file (with OpenCPN).
1. Unzip (extract) the folder
2. Open up OpenCPN and Open the Route and Mark Manager
3. Find the Layers Tab
4. Use the Create Persistent Layer button to import each of these GPX files one at a time.

Why not use the Import button at the BOTTOM of the Route and Mark Manager page?  This will import all this stuff into YOUR waypoints database.  Once imported there, to get rid of it or hide it, you have to hide each waypoint and track file.

If it is imported as a layer, you can go to the Layers tab, click one button (the eyeball next to the name of the layer) and the entire layer is temporarily hidden.  And to delete, you can delete the layer and it all goes away.

These files are as follows:
IndonesiaAnchorages47a - Anchorage waypoints all over Indonesia
Soggy Paws Tracks 2024 - Langkawi to Batavia Marina
West Indo Tracks & Wpts Sea Mi Amor Summer 2023 - Sumatra Tracks and Waypoints & Surf Spots