Mysql 8 error - Php insert statment issues and sql_db has a deprecated constructor

I need urgent assistance with a MySQL 8 error. My PHP insert statement is not working properly and I am also facing issues with sql_db having a deprecated constructor. As this project is for an existing business, it is of high priority and I need someone who is an expert in MySQL and PHP. The ideal freelancer should have experience with troubleshooting and be able to identify and fix the issues quickly.

There are 4 PHP to correct (2 attached)