Spears give you great range which can be used to great effect in a 1v1 but against a skilled player sword and poleswords are the best. In group fights however spear and shield is a very good combo, its easy to use, provides the most passive protection, makes you more annoying to aim for compared to non shield players, and reduces the chances of friendly fire. They can also be good for sticking backing, and that shield will save your life from time to time, especially when running with it on your back. They're also better against arrows.
When you attack in a slashing motion (up/left/right) you do a combination of slash and blunt. Amours are always more vunerable to blunt.
Swords = light on stam, fast, 4 directional attacks, good at 1v1's ok in group fights, starts to fade against steel amours.
Spear = ok stam, fast, mostly 1 directional attack, good in a group, fades a bit against steel armours but remains a good choice because of shield combo.
Axe = medium to heavy on stam, slower, 3 direction attacks, heavy hitter, good in group fights if you don't friendly fire. Good against heavier armours.
Blunt = basically the same as axe but does the best damage to steel armours.
Here is a helpful site for it all
https://mortal2.rocks/guides/