You still get knockback even though you have a full netherite armor. If a mob attacked you whatever kind of attack it is, projectiles or melee you will get a knockback a bug that is so annoying. Fix it ASAP.
What should happen was.... the armor must give a me full resistance in any kind of knockback except knockback enchantments and iron golem punch.
What actually happened was... I always get knockback whenever a mob or a player attacked me and even if I have a full netherite armor on.
Wear a full netherite armor and try to find a hostile mob and let it hit you one or more. From the start of nether beta the netherite armor are worthless to find they don't have speciality cuz they don't have a knockback resistance