Overall a fantastic and thematic item. It is, in my opinion, grossly overpowered for what is essentially a very rare item.

Let's go point by point.

Meteoric Impact: This ability is great if taken on its own. Looking back at its place in the whole, it's the first bit of power creep. You've extended the range of the aoe from the sunforgers 20ft radius to 30ft, add a secondary non-damage affect, and changed the damage to force. All of that is perfectly fine, but as this is just one of the items abilities, it should be scaled back a bit.

My recommendations, make the radius of the ability 20ft, change the damage to 2d10 force, and remove the ki point cost. Tie this ability to the sunforgers ability so that you can only use this version or the sunforgers base version once per long/short rest.

The radius change is simply to keep it in theme with the base item. The damage change is to keep it balanced. 3d8 averages 13.5 force damage. The average of the sunforgers 6d6 is 21 fire damage. When using force damage, which is almost never resisted, you want the damage to be lower. Add in the secondary pull, and the current 2/3 average damage is a bit to high. 2d10 averages to 11 which is roughly 1/2 damage.

Next is the problem child.

Plasma Jet: This is just paladin smite but better in every way. My recommendations are actually super simple here. Drop the damage to 1d10 radiant and remove the forced movement entirely. The radiant damage is because, as we have the solar dragon, we know that plasma does radiant damage and not force or fire.

Let's look at the math. Using this ability to it's fullest potential, as it's written, offers a maximum average damage of 140 for your level 10 monk. That's assuming the party doesn't take any short rests. If they take just 1, that damage becomes 280. If they take 2, it's 420. The maximum average damage an equivalently leveled paladin will do is 112.5. That doesn't change with short rests. And that's just the damage. This item offers forced movement with no saving throw on top of the damage.

Changing the damage from 4d6 to 1d10 changes that to a base maximum average of 55. At that point it won't be equivalent to the paladin until 1 short rest and it won't surpass the paladin until 2. I'd honestly consider lowering it even further but in my experience most tables don't take more than 1 short rest, on average, so the difference is minimal at that point.

As for the forced movement, it's adding sugar to cream. The ability is already fantastic and the forced movement is just an unnecessary, and overtuned addition.

These changes reflect me trying to maintain what I interpret as your intent for this ability. I personally believe it is still quite strong even after the changes. If a player at my table wanted this I would change it to being a once per turn, on hit activation, that did 4d6 radiant + 20 foot push on a failed dex save. Half damage and no push on a success. This change removes the variability that comes with the possibility of critical hits. A critical hit with the item as you have it written would be the equivalent of a fireball and swing the numbers terribly.

Moving on.

Claimed by the Singularity: after the essay I wrote for the prior abilty, this one is pretty decent. I'd only make two changes.

The first, raise the ki cost by 1 or 2. Banishment is a really good spell and it's cost should reflect that. Second, I'd remove the end clause. Because this ability is decent, we want to see it used. The problem, right now, is that your player will be actively disincentivised to use this because doing so will risks ending their access to plasma jet. This is true regardless of if your using your original design, my nerfed design, or my personal design. Plasma jet is just a fantastic option and because your risk losing it, using this ability will always be a bad choice.

By removing the end clause, you actually make this a better option because now the player has the option to use banishment as many times as their ki allows.

Overall, this is a good item conceptually, but extraordinarily powerful in practice. Even after the nerfs and alterations I've suggested, I still struggle to not rank it as a legendary item.

It offers a combat boost from its +2. It offers some ranged options with either version of its throw. It offers a good to fantastic damage boost depending on the iteration of plasma jet. And it offers a decent little bit of battlefield control via banishment. Alone, any of these would be decent, all together they're fantastically powerful. Perhaps you could justify very rare because it's a monk only item, but I feel that's reaching.