Here are some quick notes for those in a hurry, based on how I understood the matter myself.
In principle, that “technology testing / hundreds of wafers per day” would fit either FST/Samsung pre-production or TSMC’s FAT/SAT tests. At least TSMC will likely use standard EUV equipment in the 1.4nm node (2028), and there is a realistic possibility that testing is currently underway. It could, of course, also be Intel regarding their A14 node… My bet is on TSMC.
For me at least, that interview confirmed once again that we are following the right tracks in the media. Thanks to Atte for making the interview happen.