Re: Why bother?
I'm not sure calling Russians "Orcs" is racism, particularly if done by Ukrainians, a majority of whom are basically the same ethnic group. Had history turned out differently the capital of Russia might still have been Kyiv/Kiev. Although from the outside I don't claim to understand the culture. Belarus seems like it should be even more culturally similar to Russia, and yet that separated off after the end of the Soviet Union, and Belarussians don't seem eager to rejoin. Could there be a different version of history where a separate Ukrainian identity merged with a Russian one? Or is that just Soviet nostalgia and Russian wishful thinking?
I think calling Russians orcs is wrong. But the Russian army and government have certainly done a lot to deserve that reputation in the last 30 years. Since the Chechen wars the Russian army has done nothing wage brutal but incompetent wars with mass civilian casualties and allowed it's soldiers to commit mass rape. In the second Chechen war large numbers of the Russian army supplemented their terrible wages by kidnapping the locals and ransoming them back. When they didn't just murder them anyway. And that was in their off hours. When they weren't levelling whole towns and cities with mass artillery bombardment in their working hours. And those neighbours they haven't invaded, their government regularly threatens. Plus of course using their intelligence services for targetted murders and blowing up the odd arms warehouse. Supporting the Syrian government in slaughtering and gassing their own population, using both chemical and radiological weapons in the UK, kidnapping childern in Ukraine and sending them to Russia to be "re-educated". Plus the well-documented death-squads they sent to Ukraine. And invasion they planned utterly piss-poorly, and failed to tell some of their own troops they were due to invade, and yet had the death squads prepped and ready to go and murder Ukrainian local government and civic leaders in the bits they captured.
Russia is going to have to do a lot to live down its recent history. It might do well to learn from Germany in particular. OK their genocidal policies in Ukraine have been of the mild variety, the wholesale destruction of civilian targets, ethnic cleansing, targetted murders of local political leadership in order to further an occupation that they were unable to maintain militarily, a bit of light kidnapping of children and forcing children in occupied areas to only learn in Russian under threat of kidnapping. It's no holocaust. Although Stalin did of course kill millions of Ukrainians with a targetted famine in the 30s, and deported the Crimean Tartars en masse to Siberia in 1941, where about a third of them died - so that doesn't exactly help.
Putin has ensured that Russians are going to suffer from collective abuse for a while. And like the Germans under Hitler, quite a few Russians actively support the crimes of the regime and the rest of the people are going to have to find a way to live that down.
As for your comparison of the MARS/M142 / HIMARS/M270 system to Grad, you're just being silly. I think the Russians invented multiple launch rocket systems (MLRS) in World War II - the Allies used similar rocket artillery as part of amphibious invasions, but not in general operations. That was what the original NATO system was back in the 70s, when it was introduced. Unguided rockets with cluster munitions. And that seems to be what the Russian systems still are. With added incendiary warheads that Russia have made excellent use of in bombing cities, as well as sometimes even using them on military targets.
But NATO don't use them as the grid square removal company, like they used to - and the way Russia still does. Too many of the sub-munitions failed to go off, so the ammo was withdrawn. For mass-effect but inaccurate area bombardment NATO is more likely to use artillery. Although I think the US have a fragmentation warhead that nobody in Europe has bought for theirs yet. Even artillery is becoming a precision weapon, with laser-guided and GPS guided shells.
The updated GIMLRS guided missiles is how Ukraine were able to use HIMARS to make the bridges in Kherson unusable with precision strikes. You could measure the regular spacing between hits in some of the photos I saw. We didn't give Ukraine unguided rockets, but then they have their own ex-Soviet GRADs for that.
As for Challenger, we don't need to supply that to Ukraine. We only sent 14 because nobody else would do it. Once resistance was broken, the Leopards got sent in larger numbers, which is the better tank for Ukraine anyway. Being lighter and more plentiful. Abrams are also plentiful, but more expensive, heavier and with higher maintenance requirements. I don't think we need a large number of tanks, given they were most likely only going to be needed to defend Eastern Europe from Russia. And Russia is a tad short of tanks nowadays. Though we're currently building the Ajax, which is 40 tonnes, so if we need more than the 150-odd Challenger 3s we're making - building the hull is the easy bit. The upgrade already involves new power trains, new turrets, new electronics - and in fact new updated armour. From Chobbham / Dorchester to Epsom (IIRC) - the armour on Challenger is modular, weirdly. We couldn't build more in a hurry. But we don't need more in a hurry. If Ukraine desperately need new tanks, we'd just have to buy them Leopards or Abrams. Personally I think we need 5 more frigates, 5 more subs and and a couple more destroyers, more than we need more tanks. And it looks like that's how we'll spend our money. And if that's paid for, I'd say our next priority would be another batch of Typhoons and/or a few more F35s. NATO doesn't need us to produce more tank divisions. Poland has that covered.