I received the frame last night. Have started the build and don't seem to be having any of the same issues at this stage (touch wood). The stem is long enough to be clamped and there doesn't seem to be slippage on the stem with ~6nm of torque. Time will tell once I start riding it though.

The issue I'm facing is that the cables are extremely tight coming out of the top tube (all Jagwire cables) which is causing the front end to be super stiff when turning. And the back of the stem is ridiculously sharp which has already start slicing into one of the cables. I may need to look at some different cables for the shifting to make a bit more room.