The article / video mentions a paper discussing theoretical minimum.. I think it's this paper: https://pubs.acs.org/doi/10.1021/acs.jchemed.0c01194

> desalinating 35 g L–1 seawater at 50% water recovery has a theoretical minimum energy requirement of 1.1 kWh m–3 and a practical minimum of 1.6 kWh m–3.

SOTA is apparently ~3.7 kWh m-3. That's not a huge factor