вместо кодировки utf8mb4 collation utf8mb4_unicode_ci БД создаётся с кодировкой utf8mb4 collation utf8mb4_0900_ai_ci.
The collation (how comparisions are done)
The Unicode organization has been evolving the specification over the years. Here are the mappings from its "versions" to MySQL Collations:
4.0 _unicode_
5.20 _unicode_520_
9.0 _0900_
Most of the differences will be in areas that most people never encounter. One example: At some point, a change allowed Emoji to be distinguished and ordered in some manner.
The suffix (MySQL doc):
_bin -- just compare the bits; don't consider case folding, accents, etc
_ci -- explicitly case insensitive (A=a) and implicitly accent insensitive (a=á)
_ai_ci -- explicitly case insensitive and accent insensitive
_as (etc) -- accent-sensitive (etc)
The collation (how comparisions are done)
MariaDB [(none)]> SHOW VARIABLES
-> WHERE Variable_name LIKE 'character\_set\_%'
-> OR Variable_name LIKE 'collation%';
+--------------------------+------------------------+
| Variable_name | Value |
+--------------------------+------------------------+
| character_set_client | utf8mb4 |
| character_set_connection | utf8mb4 |
| character_set_database | utf8mb4 |
| character_set_filesystem | binary |
| character_set_results | utf8mb4 |
| character_set_server | utf8mb4 |
| character_set_system | utf8 |
| collation_connection | utf8mb4_unicode_520_ci |
| collation_database | utf8mb4_unicode_520_ci |
| collation_server | utf8mb4_unicode_520_ci |
+--------------------------+------------------------+
10 rows in set (0.001 sec)
+--------------------------+--------------------+
| Variable_name | Value |
+--------------------------+--------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | utf8mb4 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | utf8mb4 |
| character_set_system | utf8mb3 |
| collation_connection | latin1_swedish_ci |
| collation_database | utf8mb4_0900_ai_ci |
| collation_server | utf8mb4_0900_ai_ci |
+--------------------------+--------------------+
набор правил сравнения === collation, нет?
Объясните что вы имеете в виду под «Надо при создании БД явным образом задавать все опции создаваемой БД».
+--------------------------+--------------------+
| Variable_name | Value |
+--------------------------+--------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | utf8mb4 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | utf8mb4 |
| character_set_system | utf8mb3 |
| collation_connection | latin1_swedish_ci |
| collation_database | utf8mb4_0900_ai_ci |
| collation_server | utf8mb4_0900_ai_ci |
+--------------------------+--------------------+
my.cnf
my.cnf
, то этого недостаточно для корректной работы. Я выше ссылку дал на то, какие примерно должны быть настройки. Вы пробовали отредактировать свой конфиг?