MAXDOP Isn’t Really MAXDOP. It’s More Like DOP.

Here’s how Books Online describes the Max Degree of Parallelism setting:

You can use the max degree of parallelism option to limit the number of processors to use in parallel plan execution.

And here’s what the SQL Server 2019 setup screen says:

When an instance of SQL Server runs on a computer that has more than one CPU logical core, it detects the best degree of parallelism, that is, the number of processors employed to run a single statement, for each parallel plan execution. MAXDOP specifies the maximum number of cores to utilize for this instance.

Uh, no, SQL Server