Cis-genderless or Cisgenderless is defaulting to assigned sex/gender due to lack of gendered feeling and possibly lack of understanding of gender. It is similar to agender, but when asked, a cis-genderless person will give their assigned sex/gender. For example, an AMAB cis man may feel perfectly fine with identifying as male, yet does not feel any sense or feeling of being so. Cis-genderless is not inherently LGBT+, but rather a term to define the feeling or sense of gender a cisgender person may lack.
References
https://heterogen.wordpress.com/2020/01/06/growing-up-cis-genderless-without-a-word/
https://heterogen.wordpress.com/2020/01/05/on-the-term-cis-genderless/
https://www.asexuality.org/en/topic/86589-2-cis-group-cis-cis-and-cis-genderless/
https://www.reddit.com/r/AskLGBT/comments/jiyvws/are_cisgenderless_people_cis_or_queer/