A doorway page is a page that is created to rank well and has no other purpose than redirecting users to the main content. Such pages often have many links and are stuffed with keywords. The example of doorway pages also includes numerous domains that target different locations but redirect to the same main website.
Doorway pages were abused by webmasters. They were generated by machines and took little time to be created. Obviously, search engines did not like that. After a user entered the inquiry, they were presented with different search results which, in fact, led to the same content. It compromised the quality of search engines. Consequently, all companies shut down the doorway pages. Those websites that still create them rank lower rather than higher and might be panelized.
It makes more sense to invest time into creating content that brings traffic and optimizing the pages. It will create better ranking opportunities for sure while the doorway technique will only harm the website.