Wasn't there a start banner in the app, for weeks, advising that certain
camera previews were not yet fully supported? On my end, it's gone now,
but this app has rolling releases. YMMV.
If your network hardware does not allow you to set separate SSIDs for
your communication bands, then there really is no way I'm aware of to
change your phone settings. I've never used hardware that limited my
options so much. Perhaps there's a Reddit...