It is supposed to be a railway station, not a retail emporium, but its redesign has focussed on the latter. For an occasional user, its layout is very confusing. The platforms are still narrow, dank and dingy.
I haven't used New Street much since the rebuild, as most conferences that I attend are now on line, but the atrium and main connection area between the platforms should be behind the barriers. The last time I used it (pre-2020), fortunately the gates were open as I was not supposed to "break my journey" by exiting the barriers and then re-entering using the ticket that I held. Stations where one has to exit the barriers to change trains cause major problems when holding certain types of tickets. Manchester Piccadilly can also be awkward to use for this reason, and the ticket inspectors there are not very forgiving.
Whatever the criticisms of
@Bletchleyite et al, Manchester Victoria is more pleasant and easier to use.