Did you have a look at Qt (https://www.qt.io/ https://www.qt.io/, https://www.qt.io/terms-conditions/ https://www.qt.io/terms-conditions/) how they do it? They

Did you have a look at Qt (https://www.qt.io/ https://www.qt.io/, https://www.qt.io/terms-conditions/ https://www.qt.io/terms-conditions/) how they do it? They sell a lot of licenses e.g. to car industry. Note that most of their products are available under LGPL, so users are not forced to open source unless they buy a commercial license.