In this example:
bla bla bla phrase such as even if something like this doesn’t exist bla bla bla.
What can I use to inject my phrase in the middle of the sentence?
- ,phrase, (commas)
- ;phrase; (semicolons)
- —phrase— (dashes)
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
A parenthesis is an interruption. It is a remark which you insert into the middle of a sentence as if you are interrupting yourself.
In writing, the parenthesis is separated from the interrupted sentence using punctuation. You have a choice of several punctuation marks. One of them, the parenthesis, is named for this use.
Here are the marks which are commonly used for this purpose in American English. I also give common American English name(s) for the marks.
Semicolon (;) is not used for parenthesis. It is used more like a period (.), to separate complete sentences.
Style guides such as The Chicago Manual of Style will generally suggest the use of a particular mark for a particular kind of interruption. The square bracket, for instance, is often recommended when interrupting a quotation with an editorial remark:
Assuming you mean what I think you mean, I think dashes are correct here. Brackets would probably work as well in less formal writing.