Hello.
I want to learn the differences between the sGTM container and the Google Tag gateway.
If I have an sGTM container, do I need to purchase a Google Tag gateway, or is sGTM enough for every integration and API?
By the way, I integrated Facebook Conversion API and TikTok serverside tracking via Tag Manager container (without any extra gateway) and it works.
If you are running sGTM using the Gateway would be a downgrade for you 
Gateway is s standalone product for Google destination only, and would not support your TikTok and FB implementations. Stick to sGTM - you’re good.