GTM is like a funnel, once it is installed, you can pour in additional tracking code for event tracking, goal and conversion tracking, and anything else. Adding GTM support will allow BRM to support many other platforms without having to add support for each platform individually.
* Google Tag Manager will allow us to use the next generation of Google Analytics (GA4)
Please add an option to add Google Analytics, GA4 and/or Google Tag Manager. I've attached a code sample that shows how GTM is implemented - script tag in the head and no script in the body.
You could technically set it up the same way as BRM's current Google Analytics implementation, but allow for us to choose GTM, and then you will have to put the GTM ID (just like current Google Analytics ID) into the right place in the head and body noscript.
Very much this. We want to see in detail how are customers are looking at the site, and what bikes they check availability and if they give up if there is none available.