Only one of my ASINs appears when my brand name is searched (I have brand registry)

not sure why, but over the past few months i’ve noticed that my ASINs have been disappearing one by one from the search result page of my brand name.

these products are all the same product type and category. it’s a trademarked brand with brand registry. the brand is mentioned on all of my titles at the end (e.g. Big Pink Dildos by pencil_dick69). i also add it as a search term in the keywords list.

is there anything that can be done to make my products pop up when somebody searches the brand? my products need replenishing 2-3 times a year so i have repeat customers – i’m just worried that something like this might turn them away since when they search my brand, other than 1 of my ASINs, the rest of the page is just my competitors.

note: my business name is my brand name with an “Ltd” suffix. if i type the business name in full (i.e. pencil_dick69 Ltd instead of just pencil_dick69) everything shows up.