Incorrect string value: '\xF4\x80\x80\x83 for character set utf8mb4

Hello,

when inserting a Unicode text into a longtext database field, I get the error message for the character F4808083:

System.Exception: SQLSTATE[22007]: Invalid datetime format: 1366 Incorrect string value: '\xF4\x80\x80\x83 f...' for column `hzowork`.`document`.`dataContent` at row 1

According to my research on the Internet, the Unicode character F4808083 is within the allowed range of Unicode according to RFC3629.

Does the utf8mb4 character set not map the entire valid range according to RFC3629?

With kind regards
Karsten