SQL Server Processor affinity(SQL Licensing)

Due to License complaince, we are planning to reduce the number of cores of our SQL Server. Currently, we are using SQL Server 2016. Reducing the cores at SQL Instance level without reducing it at windows server is not fully compliant, which we already aware. But, before moving to a new windows machine(with reduced cores), we want to ensure that this reduction will not have any impact on performance, and whether the SQL Instance on the new machine(with reduced cores) may handle current workload. We tried this on the processor affinity but not noticing any slight change in the processor utilization. Is it the right place to reduce the number of cores of SQL Instance. Please suggest.