I have implemented the finsweet CMP on my website through web GTM. Every time I refresh the page or navigate to a new page the session gets refreshed. This is because the _ga_xxxx cookie gets recreated.
I tried to find a workaround to this by managing my own ga_session_id but that had quite a nasty side effect of getting lots of Unassigned channels in GA traffic acquisition report and (not set) for source/medium.
At the end I had to remove the CMP and move to CookieFirst. It all works fine now.
I like what you guys are doing, so I am adding this here for you to have a look at. When using web GTM / server GTM with stape something it not working and the sid of GA constantly changes. My insight is that it looks like a racing issue but I am not sure.