Honestly its kinda ridiculous that Bohemians are getting Eastern architecture set just to make them feel more “eastern”. Historically they were a part of the Holy Roman Empire, and their architecture evolved alongside German architecture. There arent any major differences at all between architectural developments in Germany and Czechia.
The central European set (the Teuton set) would make by far the most sense. This set is based off Romanesque architecture, which was very popular in Bohemia from 9th to 13th century. It also uses timber framing, which is very typical of medieval Bohemia. Of course nowadays Bohemia is best known for Gothic and Baroque architecture, but Baroque is out of this games timeline and Gothic is reserved for “western european” set. The eastern set is based off Rus architecture in feudal age and brick Gothic architecture in castle age, neither of which were ulitized in Bohemia at all.
Another point is the Orthodox church, Bohemia didnt even border any orthodox country, its quite ridiculous. Thats whole other can of worms though, because with the release of dukes of the east, 6 civs will use the Orthodox church, while only 2 of those civs (“Slavs” and Bulgarians) were actually Orthodox Christian.
Honestly, this is one of the biggest architectural mistakes in the game, especially when you can just use already existing set.