Can't you configure a tesla gen3 (18kw) charger to act as a chademo evse? Then you'd just need an arduino to talk to the type2 evse and relay the power limit (if the charger can't read it directly, not sure). I'm not sure if it's really that simple, but it seemed like it when I briefly looked into ...

I've found a unit, which does exactly what I'd/we'd like. It basically converts any standard AC source to a DC output of your choice at 22kW or more, including to CHAdeMO. It's even been around since 2017 or earlier: :)
https://www.designwerk.com/mobile-charger-22-500/
https://www.pveurope.eu/e ...

I built a charger like this for the Previa in 2020 from a Prius gen3 inverter.

Then fairly quickly I decided it was way too heavy to carry around so I removed the Chademo plug and permanently installed it to the car.
...
But do I recommend it? No. If I needed a high power AC charger I'd get the ...

I am working on this project for many months. I hope to release a full build documentation on this in the next months.
The part you seem to be struggling with is by far the most simple one. You want 22kW power from a type2 socket you can in general find on the streets. Nothing more simple then ...

Thank you. True - I've changed the title to Converter/Charger. There do seem to be a number of 15kW to 20kW, 3 phase rectifiers for CHAdeMO/CCS/etc on the market of vastly differing price and possibly quality:
https://www.alibaba.com/product-detail/DC-portable-EV-charger-30KW-40KW_1600864861093 ...

Hi, I would like to find (or construct?) a unit to convert Type 2 to CHAdeMO at up to about 22 kW. Since we have an Gen 2 Prius PHV (aka Prime) with CHAdeMO, which was imported from Japan, then this converter would enable me to fast charge from an AC source.

Our Prius has a 3.3kW onboard AC ...