Maybe the cleanest vocoder on Audiotool? Tom Scott can still be a little hard to understand, or maybe I'm just American.
The vocals and carrier synth both are split into 9 bands, and an
Envelope Follower
on the vocal is applied to each band of the carrier. The band frequencies are a geometric sequence from 300Hz to 10000Hz.
Probably could do better with more bands, but this is already kinda much.