Yes, a range extender EV like the BMW i3 REx is technically a series hybrid, but it is designed to operate most of the time on electricity only and be plugged in to charge- with a large EV size battery and a very small lightweight moped engine in the extender.

The range extender basically gives you protection from range anxiety, but isn't used at all in normal use of the vehicle. On the i3, it only starts the engine when the battery is nearly empty, but some people do software mods to be able to use the vehicle as a true series hybrid, and run the engine continuously for doing long distance freeway driving without stopping to charge.

> gives you protection from range anxiety

And grants you maintenance anxiety.

Where I live charging infrastructure is good enough that a 300-400km range EV is completely sufficient. Range extenders is a niche solution.