Bozena of Bohemia is currently listed as born in 600, parents Boleslav II (Bohemia-14), born 931, and Ælfgifu (Wessex-393), born about 915. She is supposedly married to her grandfather Boleslav I (Premyslid-5), born about 906 and is her own grandmother. Said grandfather had one probable wife Biagota, her supposed father had 4 known sons, the oldest of which could have possibly been by a Adivea who could have possibly been Ælfgifu, nothing is known about daughters.
Since the first documented Czech ruler was born about 852 there is no candidate for a 7th century Božena. All candidates for a merge have an incorrect LNAB so it shouldn't really matter who needs to have her LNAB changed to become the target for this merge. The closest candidates are Of_Bohemia-60, her LNAB could be Křesinova (Bozena, que fuit Krezine according to Cosmas of Prague), and Of_Bohemia-65, the daughter of Wenzel I and Kunigunde von Hohenstaufen.