I had heard about companies which solve this problem, i.e. they can interview candidates on your behalf if your company does not have the skills to interview the candidate. One example is Karat.com - Karat: the most trusted interviews for your technical recruiting - YouTube . But, I have never tried such companies myself. Be sure to do due diligence on such companies. Check if such companies actually have the people with experience in your tech stack. Sometimes, companies can tell lies or misrepresent themselves just to get contracts.
Alternately, you could hire one or more persons from a top quality freelancing website to help you in the interviews. Perhaps something like Toptal. Again, due diligence is important.