The on/off settings for SSL Enabled and Windows Authentication at a Visual Studio 2019 project are found in the properties pane and not the stuff you get when you right-click on a project and pick "Properties" alternatively.

F4 should open that pane. Once the "SSL Enabled" stuff is afloat, it should offer you, on the next two lines, two different ports to use for with and without SSL. In Postman, click on the wrench at the upper right and then click "Settings" to turn on and off "SSL certificate verification" when attempting to hit the SSL endpoint.