A couple things, hope it helps:
First of all, I think you need to take a closer look at your skill trees. Of course gear is important, and elemental weapons are great, but frankly, putting all those points into the red tree is kind of a waste. Particularly wildfire, conflux, and catharsis. I haven’t found those skills to be particularly helpful, and they’re especially useless against bosses.
You don’t need to copy other people’s builds, because you should play how you want to. If you don’t want to use phasegrasp for mobbing, don’t. But, at the same time, if you want to use phasecast or slam, you need to build for them. If you’re not speccing into do harm or jab cross or avatar, then you’re never really gonna get much out of those action skills, aside from anointments.
Don’t worry too much if you don’t have phasezerker. Yes, it’s probably the best com for just about any build, but you definitely don’t need it. You just need to spec your skill points around what you have.
If you have and enjoy using a bunch of elemental weapons, sure spec into anima and tempest and sustainment. The thing is though, you don’t need to put all your points in the elemental tree just to make good use of elemental guns. In fact, I’d say it’s probably diminishing returns, and not worth going all the way down to forceful expression. Sure, it’s good on all guns, but as far as I can tell, it’s much more effective if you’re using it to add elements to non-elemental weapons.
If you’re always using elemental weapons, you can just swap between whichever element your enemy is weak to, instead of bothering with forceful expression. Especially if you’re getting the swap speed from fast hands. The extra damage is nice, but you can get a lot more damage going down the blue tree to get wrath and laid bare.
I would suggest going down the blue tree to get avatar so you can make good use of phasecast. And then put the rest of your points into the red tree to get that elemental jazz you like. Maybe something like this could work for you. And if you use a lot of maliwan guns, you could swap laid bare or awakening for from rest.
You don’t need phasezerker to get rush stacks. With your elemental guns, you can pretty easily get them up with all your dots. With more points in violent tapestry, you’re getting even more dots, easier. And with do harm, your phasecast can do some serious damage to mobs, if not outright kill them.
Also, in case you didn’t know, transcend stacks. So if you get avatar, and use phasecast twice in a row, you’re getting 54% crit damage and like 60% accuracy pretty much all the time. That alone makes avatar more valuable than forceful expression on almost any build, in my opinion, especially when using phasecast.
At the end of the day, play how you want with what you have. Sometimes that might mean you don’t do as much damage as others seem to, but the whole point of the endgame for borderlands is to slowly grind your way up to get better and better gear. It takes time, so don’t fret if you’re not at the top just yet.
And if you can’t kill graveward all that quick, maybe try farming mouthpiece, gigamind, or even the creature slaughter. They have decent drops too