….so, I think I’ve got it right …..

Degradable, breaks down slowly into small plastic beads, gets into ocean not good

Biodegradable and Compostable similar but not completely. Biodegradable, broken down by microbes good, if in landfill and can’t get enough oxygen, will produce methane not good.

Compostable, best option but needs to be put on a compost heap, although some looks like plastic should not be recycled needs a compost heap then beneficial to planet good.