Minecraft wiki entry for Nether_survival, associated text: If you don't have a saddle but by chance see a zombified piglin riding a strider, you can draw it close, and ideally onto land, by wounding the rider with an arrow (or even a thrown egg or snowball), then kill it and take the pre-saddled strider for yourself. They might even drop their warped fungus on a stick for you, but the odds of that are not high. Building some walls around yourself before trying this is probably necessary, since the zombified piglins in your area are likely to turn hostile when you attack the strider jockey.