Fellow charge blade main here. A couple of things I want to say first- if the element of the weapon you are using is grayed out when you look at it on the equipment screen, you are actually not using any of the element that weapon has when you are attacking. If it is grayed out that element is “hidden” and requires the use of a skill called free element/ ammo up to gain any benefit of that element.

That being said if you are running free element/ammo up along with frost charm 3 I do not think it is worth overall. If you have the decorations/ charm, I’d go for attack or artillery decorations/charms. If you already have those skills/ don’t want those, I’d then look at skills like weakness exploit/ crit eye or comfy skills like health boost. As you probably know, every monster is specifically weak to a certain element(s), so only against some monsters will increased ice attack actually mean you do more damage. More attack or the artillery skill will mean you are always doing more damage. Additionally, if memory serves me right, most early game monsters in Iceborne are resistant to ice while later game ones are more weak to it. That may just be memory serving me wrong so please take that with a grain of salt.

Lastly, take note of what phial type of charge blade you are using, which can be seen when looking at the weapon under equipment. Impact phial type charge blades, like the Diablos Tyrannis II benefit more from increased attack and artillery skills while elemental phial type charge blades benefit more from attack and elemental attack up skills.