putting in google tag manager and testing to make sure it works

I am looking for someone has a lot of experience setting up GTM. The task is to to correctly and securely install GTM task and to test and double test that it is tracking correctly and and that bounce rates are matching up correctly with other tools such as luckyorange.com.. This may also require moving or disabling other google codes. And testing again. I am using [login to view URL] visitor session recordings to verify that the bounce rates we are getting with the GTM you install are matching up. I will give you access our [login to view URL] account so you can match up the bounces that appear on [login to view URL] match those on the GTM code. We tried installing the GTM code once and the bounce rates went to zero. We have to diagnose how to prevent that from happening again. There may be double reading of data from other google analytic code. You have to make sure that the GTM is correctly installed so that it can replace any current google analytics, google re-targeting and re-marketing and any other google code. You will see in our WordPress admin panel that we have re-marketing and google analytics plugin as well as other google code. You have to make sure that it does. You have to make sure the GTM is set up so that it is secured by our account.