https://www.gardeningknowhow.com/edible/vegetables/radish/radish-does-not-form-bulbs.htm
A few culprits seem to be: not enough sunlight, soil too compact, too much nitrogen in soil, overcrowded planting. I'd almost bet it's the nitrogen as those leaves seem very nice.
You can sautee the leaves by the way lol they're a bit stringy but not bad if you want to use the whole thing! Same goes for carrots, you can eat the greens of those as well but they're also stringy.