Can't create bootable installer for High Sierra or bellow on my new Macbook

Can't create bootable installer for old iMac (need High Sierra OS or lower) because High Sierra.pkg that I download from apple website can't be opened on my new OS Ventura Macbook. His happens because High Sierra can't be installed on my newer MacBook and, therefore, doesn't allow me to extract High Sierra.pkg -> High Sierra.app. Is there anyway around? I need to have High Sierra.app to create bootable USB to run my iMac.