Wordpress Expert to detect what is causing the high volume of database loading -- 2

We have a portal with daily cca 25.000 users but lately, there have been issues with the high loading of MySQL CPU when the admin is creating a post. When admin is trying to create a post it takes for about 5 mins for small post and for larger 15 or more mins. At the same time, the front page is working extremely slowly. The server is VPS with 12 core CPUs and 64 GB of memory. Something is not right with the database queries that is causing super slow working of the admin part and front page. We need an expert who can detect the issue and resolve it ASAP. The database is MySQL and the size of it is 1.8 GB.