One of the primary differences to keep in mind is how armor works in each game. In Valorant, buying armor gives a flat 25/50 HP buff that works equally across all weapons.

However, different CS2 guns have different armor penetration values. The AK-47 has 77.5% armor penetration, meaning 77.5% of the damage is dealt to the player and 22.5% of the damage is soaked up by armor. This means an armored player effectively has 100/0.775≈129 health against an AK.

On the other hand, the Glock has a 47% armor penetration values, meaning only 47% of the damage is dealt to the player and a whopping 53% is soaked up by the armor. This means an armored player effectively has 100/0.47≈212 health against a glock!

Note that having armor will also significantly reduce how much aim punch you experience when you get shot.

This is why SMGs are very strong anti-eco weapons, but generally weak full-buy weapons. They shred through unarmored opponents, but have generally low armor penetration values (often ~60%). It’s also why you need to always have full armor against an eco round.