mysql> select 'ἐν' = 'Ἐν' collate utf8mb4_0900_as_ci;
+----------------------------------------------+
| 'ἐν' = 'Ἐν' collate utf8mb4_0900_as_ci       |
+----------------------------------------------+
|                                            1 |
+----------------------------------------------+

mysql> select 'ἐν' = 'ἕν' collate utf8mb4_0900_as_ci;
+----------------------------------------------+
| 'ἐν' = 'ἕν' collate utf8mb4_0900_as_ci       |
+----------------------------------------------+
|                                            0 |
+----------------------------------------------+