Some of the credit card companies will be more wary of Covid related charge-backs after they were found to have incorrectly refunded people for flights that did operate even though the restrictions meant they couldn't travel.
I don't know the details of the Austria lock-down, but if the apartment is available for use, then you are still obliged to pay for it I'm afraid. I'd recommend looking into the details of the Austria lock down in the hope that this business will not be allowed to operate, and so will be unable to charge you for a service they are not permitted to provide. Perhaps contact them and ask them what the story is?