cut to the chase "to talk about or deal with the important parts of a subject and not waste time with things that are not important" (source)
ell.stackexchange.com/users/4910/Jules
The grammatical context will dictate the kind of expression to use.
There are dozens available but the one that occurs to me is "Getting down to the nitty-gritty", which I suppose means pushing aside vagueness, irrelevancy, distraction and other smokescreens and exposing the grit i.e. the hard, abrasive kernel of the matter.
This is, however, not easy to use and requires a certain informality of context.
Otherwise adverbs like "Basically", "Fundamentally", "
In essence" at the beginning of an appropriate sentence could do the job.
ell.stackexchange.com/users/35032/Ken Wilson
One common idiomatic expression is... getting down to brass tacks ...which is of uncertain origin , though there are several more or less fanciful theories.
In my experience the primary sense is of addressing fundamental principles in a discussion, but it can also be used to mean getting serious or dealing with fine points of detail (in a barter/negotiation context).
ell.stackexchange.com/users/126/FumbleFingers Reinstate Monica
"The heart of the problem"is probably used most in everyday speech.
However, "the crux of the problem" or "the crux of the issue" is often used in a more formal setting such as a research paper or a speech.
ell.stackexchange.com/users/36126/Raj Srivastava
Don't beat around the bush
See definition here
This is suitable in an informal context.
To answer more thoroughly we would need more information
ell.stackexchange.com/users/20013/laureapresa
I would like to know one expression that means the same as "Going to the root of the problem..." Could, you please, let me know the expression and the meaning of it?Thank you in advance.
What expression could be used in English to say that you want to discuss to the root of the problem directly?
ell.stackexchange.com
<expressions>
ell.stackexchange.com/questions/91863
ell.stackexchange.com/users/35058/user3470151
Cut to the chase, get down to the nitty-gritty, get down to the brass tacks, get to the heart of the problem, get to the crux of the matter, and  let's not beat around the bush are all expressions that could be used. In essence" at the beginning of an appropriate sentence could also work. Some options are: "Cut to the chase", which means to focus on the important aspects and not waste time with things that are not essential, "Getting down to the nitty-gritty", which means setting aside anything vague or unimportant and exposing the core of the matter, "Don't beat around the bush". Another similar expression of uncertain origin is "getting down to brass tacks". Additionally, in everyday speech, "the heart of the problem" is often used or "The crux of the problem/issue", which would be synonymous but more appropiate to a formal setting. Using "In essence" at the beginning of the sentence could also work. Since the grammatical context determines the expression to be used, more information would help pick the most accurate one.
Since the grammatical context determines the expression to be used, more information would help pick the most accurate one. "Cut to the chase", which means to focus on the important aspects and not waste time with things that are not essential. "Getting down to the nitty-gritty", which means setting aside anything vague or unimportant and exposing the core of the matter. Using "In essence" at the beginning of the sentence could also work. Another similar expression of uncertain origin is "getting down to brass tacks". In everyday speech, "the heart of the problem" is often used. "The crux of the problem/issue" would be synonymous but more appropiate to a formal setting. "Don't beat around the bush" is also an option.