Hi Tim,
It seems your server does not have mb4 support, for this case, simply check two options Force UTF-8 collation on database and Force UTF-8 collation on tables. Like so https://imgur.com/a/3ut1oJq
Same issue: https://www.akeebabackup.com/support/akeeba-backup-3x/Ticket/26278-error-1273-during-a-restore-of-database.html

Or you can ask your hosting add support for utf8mb4