I'm extremely skeptical of any claim that hybrids are better for the environment than EVs in aggregate, but for specific use cases over certain timeframes the difference may be small.

On the one hand, volume versus weight an ICE engine is generally "lighter" than if that equivalent space were tightly packed with battery cells.

But on the other hand a car is not going to tightly pack the equivalent volume, most modern EV designs are a "skateboard" layout with all the batteries on the floor of the car. The front hood of the car is typically at that point unused space and many modern electrics place there now a "frunk" ("front trunk" or "froot"/"front boot" if you prefer Britishisms) for "bonus" cargo space.

From that perspective, a hybrid has "free" space for a gas generator by taking "back" the frunk space, but they have to shrink the battery because of the added weight of the gas generator. (The skateboard has the physical space either way, it shrinks to keep the overall car weight below an aerodynamic threshold, not to yield space for the gas generator.)

For many people that initial price difference is high enough that buying a BEV instead of HEV makes totally no economical sense - so likely the lower emissions from usage are not going to offset higher emissions on production, for the whole lifetime of a car.

The BEV economics work only if you drive really a lot on long distances, but that's unfortunately the area where BEVs lose to HEVs on convenience.