are redox reaions are chemical displacement reactions/?

NOT all redox reactions are displacement reactions.

For example : 2Na(s) + Cl₂(g) → NaCl(aq)
This is a redox reaction because the oxidation number of Na increases from 0 to +1 (oxidation) while the oxidation number of Cl decreases from 0 to -1 (oxidation).
However, this is a synthesis reaction, but not displacement.

Technically, no.