Louis Davidson starts digging in:
There are three major “engines” in Fabric that I have seen that use T-SQL. There is the SQL Azure Fabric engine, the Lakehouse, and the Data Warehouse. Having this capability to manipulate data is wonderful, but there are some things you need to understand before you start writing code (unless you want to learn them the hard way like I have. I also will not profess to have found all of these differences. Changing my mindset when using these engines was the subject of this editorial
Read on for some inconsistency.