I've lately decided to attempt writing a series of short stories starring a consistent sleuth character, much like Doyle's Sherlock Holmes and Christie's Hercule Poirot. This was mainly for practice so I could get experience for a project on much larger scale. I attempted to make his personality distinct from the typical sleuth character, who were often solemn if not just rarely making exceptions to tease their assistants, usually employing logic and investigation methods that were, until explained, understood solely by them. From this, I created the rough overview of a character named Ernis Blythe, who possessed a sense of humor encompassing anything from light to sometimes downright unacceptable jokes, who flourished in a social setting and was observant of people's ticks, quirks and body language and investigated primarily by making observations of the crime scene and adjacent areas, discussing it to acceptable degrees with relevant persons and finding how their body language's juxtaposition with what they say presents a conflict with what he knows. But when I tried to apply this, circumstance and various other parts of his character conflicted in such a way where he'd be driven to behave as a sleuth archetype. What would be a way to break from this character type?
How about a cowardly, timorous sleuth? Or paranoid sleuth? A psychopathic sleuth? A Donald Trump sleuth who dreams up solutions and is then outraged when his dreams are demonstrated to be nonsense. Or an obsequious sleuth. Or a shrewish sleuth.
How about a divorced, absentee father, functioning alcoholic who is married to his job.... oh wait, that is the detective in every noughties crime drama. Probably my favourite TV character of all time is Columbo. The shambling, absent-minded unsophisticated pretence that hides a keen intellect as he weaves his web around the killer. I also like Barnaby (John Nettles) from Midsomer Murders, because he is just a normal family man who lives a contented life- what a blessed change from the dreary depressives you normally find in crime dramas. And I enjoy Sherlock Holmes and Poirot as you mentioned.
This might sound silly, but look at something like Ace Ventura to see how a different take on the character type can work.
1st person narration. Every chapter starts with him referring to his notes to try to remember what he's supposed to be doing.
It's a bit different to pull off memory loss in a story. I haven't actually read the story that inspired Memento. It's a killer film, though!
Perhaps you are thinking too much. Start writing something, a story, a plot and let the character come to you. You could start with how he got the mand "Ernis Blythe." I assume that's a guy's name. How did you choose it. How did he get it. Why? That's a start. https://www.kabalarians.com/m/ernis.htm
Your idea sounds a lot like House (minus the social part!). Although he is not a crime detective, he is a detective of sorts. You'll probably find you'll have to adhere to certain features for the character in order to make it believable. I crack smoking, part-time street juggler, is unlikely to be believable as a sleuth (for obvious reasons); although for comic effect a Pet Detective worked well enough! The best way to go about this is probably to frame the characters background, Holmes was in the British army, Sherlock was not in the police force, then there are the TV shows of another doctor and a writer taking on the role of sleuth. An interesting choice of occupations and background history would be enough to make a fresh character I think? So, my advice would be to focus on the characters upbringing, location and daily job, before getting into their psychological depths. Good luck
How about someone similar to Archie in the Nero Wolfe series? I haven't actually read any of the books, but I've seen a few screen adaptatations, and Glen Cooke's Garrett P.I. series draw heavily from them. Archie is handsome, good with ladies, and pretty happy-go-lucky, as I recall, doing all the legwork for Wolfe (or the Dead Man, in Cooke's books), who stays at home and does the thinking.
Actually, I'm happy you mentioned this, because both his first and surname refer to elements of his character, though the characterization and extra defining has been a bit of a hurdle for me, as I said. Ernis, like the link you posted, was meant to represent the creative (or clever) mind a detective would certainly need. I wasn't sure if this would be an important detail before, but I'll note it... he'd imagine things as being far more complex and off-the-wall than they really may be, usually "on the right train of thought if the train was going on a wild frenzy." Blythe actually was meant to refer to his >>>>>>blithe<<<<<< nature, his natural sense of humor and his casual consideration of darker subjects when he speaks of them.
Actually, this is very helpful! I can even add on to the importance of crafting a well-defined upbringing (that may be presented consistently through otherwise inconsistent stories) in that, one's upbringing, experiences, occupation and training will certainly help define their perspective and perspective is an important part of how a sleuth will go about solving cases, as well as how they will look at the cases, define what triggers urgency in them and whatnot. I can see how mystery novels would, arguably, rely on perspective more than many other genres, definitely.