GI rights do not cover plan N.
True, but unless things have changed, Anthem (GA) had/has plan N as an option for GI. As of 2023 this appears in the GI section of their app.
Anthem offers the following
Medicare Supplement
insurance plans, if you are
eligible for Medicare when
turning age 65 or by disability...
Prior to 1/1/2020, Plan A
or F. In addition, Anthem
allows you to enroll into
Plan N.
• On or after 1/1/2020,
Plan A or G. In addition,
Anthem allows you to enroll
into Plan N.
Carriers are allowed to offer more liberal options but not more restrictive.