wpmu_new_blog hook has been deprecated. Use wp_initialize_site instead.

[asaquzzaman]

Please use this hook wp_initialize_site instead of wp_insert_site on deprecated message. Because if we use wp_insert_site hook, we couldn’t access wp_options table for newly created sites eg: updating option table data with update_options with error message:
WordPress database error Table 'ex.wp_10_options' doesn't exist for query SELECT autoload FROM wp_10_options WHERE option_name = 'ex_version' made by wpmu_create_blog, wp_insert_site, do_action('wp_insert_site')

[SergeyBiryukov]

Follow-up: ​#WP49612