Mr_H
Given the need for speed here I’d look for an ex-commercial large flat burr grinder, something with a timer ideally so you can at least get close to a required dose each time without having to weigh out every dose. Anything with less than 64mm burrs is probably going to be too slow.
A Mazzer Super Jolly Electronic will probably do a 17-19g dose in about 10 seconds and I’m guessing but probably £200-400 used.
You might be able to find a 83mm like a Ceado E37 or Mythos One for around £500 if you’re lucky which will rip through a dose in about 5-7 seconds.
There’s also the Mazzer Major as another option.
If you’re really limited on budget then a Mazzer Mini E but it’ll be slower.
All of the above are commercial grinders and very reliable/robust.