This might be a bit weird, and I'm not sure if this is the right place but... Does anyone recall a manga with a dedication of some sorts at the beginning (or end) much like a book dedication, such as "to so and so, my beloved something something". I don't ever recall seeing a mangaka dedicating their work to someone.

Yes. I don't remember any specific titles but I have seen it. Normally it is on the last page of a volume or the end of a season.
Examples I have seen

• To their editor who supported them through the process and helped brainstorm
• to their assitants
• to friends who convinced the mangaka to draw and publish an idea
• to their readers in general
• to a specific anonymous reader (often a specific piece of fan mail that was supportive)
• to family members
• Once I saw one to their cat
• TLDR: thanking or in memory of staff, friends, family, pets, fan, editor, readers etc

I wonder if I should have been more specific. Just to make sure, I don’t really mean the thank you messages at the end of a manga which are plenty. I mean a genuine dedication much like the ones you can find at the initial pages of a book such as “ to my dear brother so an so”. You know, much more poetic sounding and usually very short with a whole page dedicated to them (not all are strictly necessary but you get the gist). Although among the ones you mentioned the one with the cat sounds like a dedication. If you ever remember the title I would love to take a look.

I didn't mean the general "Thanks for all the support, I couldn't do it without you type message." I was referencing the ones that are specific. A dedication in a book is expressing thanks or an acknowledgment . It is often someone who inspired or supported the author. Often with messages like "this work would never have happened without xxxxx". This type of dedication is what you normally find in novels, they can be anything from a few words multiple. One of the best I have ever read is also one of the longest (9 pages in a paperback novel). It was in the novel "Isle of View" by Piers Anthony (He later published an entire book about the person he dedicated one of his Xanth novels to Link to google book description)

I meant the times where it is something like.

• I never thought I would make a manga. My best friend listened to me talk about this story for years, they pushed me to actually try and supported me through it all. This manga is for you 'best friend'.

---Cat dedication information
I don't remember the title sorry. Or the plot.

Things I remember about it
100% sure

• manga (black & white, divided into volumes, page format)
• fan translated
• the dedication was a short extra at the end of a volume

99.99% sure

• mangaka's had a picture of their cat above their name on the manga book cover flap (Similar to hardback book jacket flaps that sometimes has the authors picture and blurb)
• cat in the story

90% sure

• BL (Yaoi or Shounen Ai)