Short answer: yes, we outlined only some of the problems. Characters not encoded properly, normalisation wrong (and breaking the char-glyph model). That’s all on Unicode. Then shaping engines apply rules wrong (bundling Greek with Latin and Cyrillic pushes a lot of assumptions on both Gr and Cyr)

Indeed we have been circulating resources for literally decades. The W3C gap analysis is full of “needs research” for information we have shared with OEMs and developers similarly. Those “needs research” entries should be followed by “hm, let’s Google for Greek experts”. I/We are not hard to find.