Depending on what instruments you have in your score, there’s a pretty common workaround for getting Dorico to display the “wrong” time signature that could work for you, but only if you don’t have any grand-staff instruments like piano (as in the attached pic) or staff groups where the barlines will draw across all instruments in the group. I realize that probably covers most scores, but if that happens to not apply to you, it should yield pretty good results.
Simply set the initial time signature to 11/16, then add dotted barlines where they belong in the first measure. Then in the second measure, enter the correct aggregate time signature and hide it.
It could potentially be possible to get Dorico to break the dotted barlines drawn across a grand staff or staff group (making this better than a “sometimes solution”), but if so, I couldn’t sort it out, despite fiddling with the engraving options and independent time signatures and the like.