Although hardware IMEI may be difficult to change, GrapheneOS (and perhaps others) have a way of intercepting system service calls which enable users to supply the values.

On Tue, Dec 28, 2021, 8:10 PM grarpamp <grarpamp@gmail.com> wrote:

Point of sale tracks the IMEI, being able to change
that for any/all phones is useful, such as for giving
your phone away to others.

Point of sale tracks the SIM, but unfortunately a SIM
is probably still not generateable onto blank cards?