Ingest from the original camera card. Also FCPX is not like Premiere in terms of MTS files on a timeline. Normally you would optimize that format to ProRes HQ or Proxy- which are checkboxes in the Ingest Window.
But it looks more like a major system problem than an FCPX issue like you are tied to a network connection that is stuck, your HD or RAM is failing or perhaps a system virus scanner or indexing app is slowing everything done to such a high degree.
I can ingest and begin editing in a couple of minutes off a GH4 on my 2015 MBP.
Noah
FCPWORKS – FCPX Workflow
FCP Exchange – FCPX Workshops
XinTwo – FCPX Training