Given the question expressed in the title, it is important to emphasize a recurrent linguistic practice - the use of “same” in the pronominal function, that is, when this is used in order to replace a pronoun or noun. Have you (the) used it yourself?
If so, it's time to understand that this is an inappropriate placement. But let's look at some examples that will allow us to better understand how the fact really happens:
In the face of such placements, let us lend ourselves to the exercise of attributing proper use to anaphoric elements (terms substitutes) in question, in order to make the speech adequate to the linguistic parameters, as well as evidence:
Thus, at the expense of the recurrence in question, we chose to use the personal pronouns of the straight case – they, he.
But isn't it that the “same” can be perfectly used in other circumstances? Yes sure! is what we will see from now on, note:
* As an adverb, once denoting “justly, even, still, in fact”.
It is right here, in this heavenly place, that I want to spend my vacation. (it's right here)
* As a noun, whose semantic meaning (sense) refers to “the same thing”.
The same thing I told her, I told you too. (the same thing)
* In some expressions referring to “to give in the same, to give in the same, in the same”, which are equivalent to “in the same state, in the same situation”.
Advising him or not is the same thing. (the situation is the same)
* As a concessive conjunction, referring to the “although”.
Even exhausted, she does not stop practicing physical activities. (although exhausted)
* Functioning as a pronoun/adjective referring to the idea related to “identical”, “proper”, “exact”.
They solved everything themselves. (themselves)
By Vânia Duarte
Graduated in Letters
Source: Brazil School - https://brasilescola.uol.com.br/gramatica/utilizar-mesmo-mesmo-correto.htm