I've used these (150mm x 10mm ones) and my elu 12v impact driver put
them into softwood fine without a pilot hole.

That's good going, even for an impact driver. You're pushing the
whole150mm into the timber?

I use 6x100m and similar turbogold a lot, mostly in mahogany or oak,
predrill at 3-4mm (with a clearance hole in the attached timber) and my
14.4v bosch impact driver can start to slow. Pushing harder than that
and it's very possible to snap a screw. Lube helps a bit.

10mm is unlikely to snap, but what about it simply locking solid (and
unwilling to reverse out) before fully inserted?

How close to an edge can you go with 10mm, without pre-drilling? Did
you lube them? Did you get any cracking along the grain?