Your situation sounds similar to mine: several rejections of a long-ish paper from top journals. A small number left to try before moving to lower tier. This "answer" will use that as a guide to give you advice.

I have several relevant posts here about it. In my situation, it is a blessing because I found better arguments and now legitimately have more than one paper.

The comments and answers to my questions are probably relevant here: have variable and trusted readers give you honest and through feedback. That will help you decide what to leave out if anything.

Follow the standards of the discipline and the journal you wish to submit to. This includes the writing style and paper format. If it is typical for things to be left out, then do that. You say this is your first paper, and that means there is an additional challenge due to lack of experience. My situation is similar--although I am mid career and have several papers, this is my first truly top-journal worthy result. The challenge is purely about presentation/style. I suspect that is a big factor here. "Style" could also be construed to include things like leaving out standard or simple arguments. That will depend on discipline/journal to a degree.

Much of this comes down to editor and referee subjective preference too. There is luck involved as well -so I have been told at least.

I was unable to get any thorough/careful qualified readers for my paper (the main thing people suggested I needed), but the extremely limited amount of feedback I got was IMMENSELY helpful (from real, even somewhat "famous" experts). That plus deep introspection, hard work, and much rewriting will vastly improve my paper. Plus presenting the work to an audience helped. Even if I still can't get it at a top journal, the paper will be accepted somewhere. It's for the love of the knowledge and sharing it that matters, even if it's not immediately (or ever) honored by those at the top.

I hope that is helpful and doesn't just come across me wanting to talk about myself. I truly get the situations were similar and that these comments might be helpful.

Best of luck!

Your situation sounds similar to mine: several rejections of a long-ish paper from top journals. A small number left to try before moving to lower tier. This "answer" will use that as a guide to give you advice.

I have several relevant posts here about it. In my situation, it is a blessing because I found better arguments and now legitimately have more than one paper.

The comments and answers to my questions are probably relevant here: have capable and trusted readers give you honest and thorough feedback. That will help you decide what to leave out if anything (and generally how to improve the presentation).

Follow the standards of the discipline and the journal you wish to submit to. This includes the writing style and paper format. If it is typical for things to be left out, then do that. I do find that top journal papers often day things like "it is easy to see X" and I personally don't like that, but if that is the cultural standard, it is what it is and might be advised to follow it. But there is no guarantee that yours is treated exactly the same as other papers. You say this is your first paper, and that means there is an additional challenge due to lack of experience. My situation is similar--although I am mid career and have several papers, this is my first truly top-journal worthy result. The challenge is purely about presentation/style. I suspect that is a big factor here. "Style" could also be construed to include things like leaving out standard or simple arguments or the specific way/order things are owned in (the flow of the arguments). That will depend on discipline/journal to a degree too.

Much of this comes down to editor and referee subjective preference too. There is luck involved as well -so I have been told at least.

I was unable to get any thorough/careful qualified readers for my paper (the main thing people suggested I needed), but the extremely limited amount of feedback I got was IMMENSELY helpful (from real, even somewhat "famous" experts). That plus deep introspection, hard work, and much rewriting will vastly improve my paper. Plus presenting the work to an audience helped. Even if I still can't get it at a top journal, the paper will be accepted somewhere. It's for the love of the knowledge and sharing it that matters, even if it's not immediately (or ever) honored by those at the top.

I hope that is helpful and doesn't just come across me wanting to talk about myself. I truly get the situations were similar and that these comments might be helpful.

Best of luck!