Edit the database backup file and replace utf8mb4_0900_ai_ci with utf8mb4_general_ci and CHARSET=utf8mb4 with CHARSET=utf8.

Linux users can use the sed command to replace text in files.

sed -i 's/utf8mb4_0900_ai_ci/utf8_general_ci/g' backup.sql  
sed -i 's/CHARSET=utf8mb4/CHARSET=utf8/g' backup.sql