You can't fire someone at will like in the US, you need to justify the decision. Which takes some time and paperwork. Also, it used to be risky as the fired employee could sue and ask for damage, with no legal cap. The later has changed. So you can fire people, I've seen it done a few times, if you have a competent HR it's perfectly doable. You will need to document why and have some justification, and be ready to present your case if challenged.

Also, it's possible to let someone go my mutual agreement, with the employee keeping their unemployment benefit (there are limits to prevent abuse). It also eases things when both sides agree there's a mismatch, which often happen.

So it's definitely not as fluid as in the US, but not stuck as some people would let you know. You tend to be more cautious about the hiring for sure.