The Perfect Solution
Basically wordpress is working on the database query therefor like to recommend you first generate the two backup for the database in the database.sql format and database_ori.sql
Now manually replace all the instance for http://domain to https://domain in the database.sql file, once it complete restore the database database.sql in the wordpress database...
If anything goes wrong you can simply restore the original database from the backup copy database_ori.sql
Let me know the result
Basically wordpress is working on the database query therefor like to recommend you first generate the two backup for the database in the database.sql format and database_ori.sql
Now manually replace all the instance for http://domain to https://domain in the database.sql file, once it complete restore the database database.sql in the wordpress database...
If anything goes wrong you can simply restore the original database from the backup copy database_ori.sql
Let me know the result