Do not forget that datasheet is from 2018, referring to order numbers. And a 02CY644 should work at full speed in a Blackbird, according to this chart.
First of all Clemens Ladisch already answered this question two weeks ago ... Second, why does someone buy a card for several 100$, which does not work under Linux?
The question is actually to whom does IBM sell individual CPUs. I can't think of anyone. Even if you buy POWER systems from Thomas-Krenn you will not get CPUs from them. But it costs nothing to ask them.
You could also check the OpenPOWER page to see which European companies are members and ask them.