English muffin collapsing

The cold proofing isn't really an optional step here. Your options are pretty much to follow this recipe, or if you really don't want to refrigerate overnight, find a different recipe.

If you keep that proofing step, but do it at room temperature instead, things will be off: you probably have too much yeast, and you'll likely end up overproofing even if you try cut the time down to a normal room temperature rise time. Overproofing tends to result in expanding gas overwhelming the gluten structure and blowing out, so the bread will collapse. I think this is what you did.

If you skip that proofing step entirely, then you'll have underproofed. This also leads to a more collapsed result, because the gluten hasn't strengthened enough yet, so instead of stretching it just tears, and along with that, there's not enough gas released, so there's just not as much volume to work with.

There are some really great detailed descriptions and photographs of examples of under- and over-proofing in this Serious Eats article on troubleshooting bad bread.

You could probably adapt by reducing yeast and finding the right amount of rising time for a room temperature first proof, but you'll waste less time experimenting if you just find a new reliable recipe instead of modifying this one.