Dandelion green are bitter more like chard or collard greens cooked (though uncooked chard and collard greens taste a bit like broccoli and dandelion greens simply taste bitter uncooked.) I have a book called “Wild foods field guide and cookbook” that says for dandelion greens:
“…it’s a good idea to blanch or par-boil them before proceeding…” with cooking them. I haven’t tried this method yet but plan to try it this summer. My guess is that salting and spicing them will make a huge difference too.