Custom menu – how to set up taxonomy to show 'standard posts' only

First of all, thank you for this beautiful theme.

I am referring to the shamrock demo https://demo.mekshq.com/?theme=shamrock.

I managed to set up my custom submenu for the formats gallery, image and audio, https://www.ingereck.net/type/post format, but this does not work with ‘standard posts’:

“Note: When writing or editing a Post, Standard is used to designate that no Post Format is specified. Also if a format is specified that is invalid then standard (no format) will be used.”(https://codex.www.ads-software.com/Post_Formats).

I also want my home to show ‘standard posts’ only.

I searched the internet for a solution, also found answers such as this one:
https://stackoverflow.com/questions/7486763/only-show-wordpress-standard-post-format-on-template, but do not achieve getting it to work, may be because I am not hooking it up right in my child theme.

Any suggestions?