Our team has conveyed:
The innodb_page_size is read_only server parameter in Azure Database for MySQL Single Server and Azure Database for MySQL Flexible Server and cannot be changed because innodb_page_size can only be configured prior to initializing the MySQL instance and cannot be changed afterward.
Please convey your use case on why you want to update this server parameter? As conveyed by the team,,migration should not be a problem if this parameter value is different but we would still advise to create test environment and check that.
Regards
Navtej S