true or false stranded wire cannot be connected on a scew terminal(i.e. switch)
without the use of a terminal knife/ring connector? please reference nec article.

h2O

All UL listed devices for use with 14, 12 and 10 AWG are suitable for solid or stranded conductors.

That info. can be found in the UL White book.

Yes, UL White Book page 100 under "Termnial" subheading of the "Receptacles for Attachment Plugs and Plugs (RTRT)" heading