How do mass layoffs work in places like the EU?

I know it's much more difficult to fire people in the EU, but is there an exception if it's done as part of a layoff?

The only real solution I can think of is regulatory in nature (e.g. requiring paying out 6 months pay during a layoff, which might make companies think twice before "hiring ahead of growth")

Because let's face it, "hiring ahead of growth" is the real problem. These companies aren't firing people because they are making less money. They're firing people because they hired people before they actually needed them, in anticipation of future growth that didn't materialize.