
I know you aren't deceive since is even in the tittle and in the first chapter, but the setting seems so.... unnecessary? I don't think it would have changed that much if "she" was presented as a guy from the start, it's pretty much the same plot of "Sincerely: I became a Duke’s Maid" except in this case the young master is the protagonist and not the villain.

No, that’s not true. The reason that the ml is pretending to be a girl is because if he wasn’t the the duchess would have killed him already in fear that he would be in the way of the inheritance. Not dying seems pretty necessary for me. Also, although both of those manhwas have similar themes, it’s best not to compare. :))

That's the justification they come for, is not really that much of a good reason, it doesn't really upset me, it just seems unnecessary for me, the story could have easily made him a guy from the start and roll with it without problem, I mean, is not the first time a situation like that has appeared in this kind of fiction setting, in fact, the stepmother abusing her non-biological children to the point of wanting them death despite being boys or girls is fairly common, like, too common.
The thing is that the pay off of that "secret" is not so "heroine" can open his heart to MC and so share the secret and bond even deeper, the pay off of to that is so MC can go like "wHAAAAaaaaaaaat u were guy all this tiiiiiiime omg!"
And this isn't really a comedy to go for that route, there are works such Ouran Host club, Mayo Chiki, Girl fights boy, were the gender change has a purpose and a pay off, such a comedy, situation between the protagonist and the co-protagonists regarding gender, bonding, if you take away that from those works you don't have a story and have to make a lot of changes to give it a sense, heck, even Mulan counts on this.
Take this as a critique and not so much as a c0MplAint, I still like this work and think is good enough and will continue reading, I just I can't overlook how useless this specific setting is, if they exploited more for comedy purposes like in Aoharu x Kikanjuu I would like it and get, but heeeeeeeeere, is, nah.

It isn’t really a setting, “her” actually being a man is more of the entire plot. He could have not pretended to be a girl, but he did and that’s the whole plot. You take that away then you take the whole plot. I mean you could but would it still be the same manhwa? The plot’s also not that deep so i think the “justification” was well enough. And yeah, it’s pretty common but just because it is doesn’t mean they have to be the same each time, right? I guess that’s why the author made this little twist, or maybe the author genuinely just wanted to make something a bit gender bender. Also, that kind of pay off seems a bit of an exaggeration. What the story could have been or what the author should have done, the story is as it is. We’ll just ride along and see where it goes.
The only unnecessary thing i found here is your “critique.” Lastly, I will stop replying. I think I just started an argument but it’s currently 2:31 AM and I’m too lazy to finish what I started. Peace out ╮( ̄▽ ̄)╭

Why are critiques unnecessary?
The plot is pretty much 'healing' and romance, the bond it would form between heroine and Mc, is like, you don't know the definition of plot and can't handle people criticizing something.
"the main events of a play, novel, film, or similar work, devised and presented by the writer as an interrelated sequence.
"the plot consists almost entirely of a man and woman falling in love""
If I take that away with minimum changes I have pretty much the same story, I mean, after all it's pretty much Sincerely: I became a Duke’s Maid anyway.
If the heroine was a woman from the start or was presented as a man the story would remain pretty much the same and would have the same type of character.
For example Mulan, take way the fact she crossdress you can't start the story, since that is that important for the plot, make her a man from the start and you don't have the same character.
I get wanting to do genderbender, BUT, here that isn't really exploited which is one of my concerns, it's verily a thing, I really would have preferred for MC to know the secret, so they could share something intimate like that, the author didn't seem to want to go for that route as the first chapter showed it, as I said, the pay off of this it's just "whaaaaaaaaaaaaaat u were a maaaaaaaaan?"
Are people really complaining that this isn't gl webtoon? I thought this was obvious from the title, the tags and the first few chapters about what this was going to be like. Just cause it's not don't let that ruin your enjoyment of the story. There are plenty of gl stories that can read on here.