FTR, this is not exactly so. Not all a-milleniallists believe in a 'literal" tribulation, at least not in any sense of a "time period', that hsa any definition or limits. In fact, most a-milleniallists do not believe this, (and especially in any 'rapture', which is by definition, the "taking out" of the saints from the world), but rather in a 'sudden' "ending of this world" at "judgment day", and the start of 'eternity'.
And there are all sorts of flavors of all views on eschatology, as I have previously posted, and among Baptists, at that.
"All" is just too broad a brush to paint with, in most cases, on prophecy.
You might also note that "post-trib", as a general category, has to do with a Post-tribulational rapture, and pre-millennial return of the Lord Jesus Christ, and not any a-millenial view.
"Rapture" and "return" are not synonomous, by any stretch.
Ed