Refugees are fundamentally a burden. It is just how it is when you are accepting displaced people on short notice. You accept them because it is the right thing to do, not because they benefit your country.
It's reported that thousands of companies are offering jobs, but there are millions of refugees. Someone is paying the cost of feeding them, housing them, and giving them essentials if they can't provide for themselves (likely, considering the whole war-torn refugee thing.)
Many Ukrainians probably have skills, but this isn't on a timeframe where that will be valuable to the host country and the thing about refugees is once the war is over they get sent home.