I personally believe that we as humans have a terrible habit of feeling guilty, of being considered lazy and being put in a place where "where the ones at fault".
The things happening in the world, are not necessarily our fault, there could be generational things, a bit line of previous actions from other individuals who created nowaday's circumstances.
I had my period of time back in high-school where I stressed over climate change, politics and whatever. Trying to do something sadly, is limited, by time and money... but there is a factor a lot ignore, influence.
Why celebrities or well known content creators are the ones mostly doing donations to benefic causes? Because of how well known they are, if one of them, let's say The Rock or Misha Collins were to get involved in politics (Besides their Go Vote campaings in USA and like other things like voting for a less-likely coup president like it happened in Brazil) then they'll have a higher influence and a bigger network that'll allow them to do stuff without as much limitations as some unknown rich individual that has no influence and is not known by anybody and the most common logic of the people is "Better work with a known devil than a devil to know".
Otherwise, ask me why a Contemporary artists associated with the populist politic party, not known by anybody but the elites because she also works for the Government and the Ministry, manages to make political art of said politic party and hang it in museums despite of being talentless and also a plagiarist? (This is the Fatima Pecci Carou case from my country)
I don't think we need spiders or mosquitos, but they are also essential to mother nature, they are essential in the chain food even if I see no value in their diminute lives.
If you feel art is useless, then... what you do with art will feel useless on your own standard. Maybe you'll need to seek another career and do both, one that is "benefitial" for the greater good, and the other to be "selfish" so you won't be in said dilemma or won't feel completely devastated and a culprit of something that is out of your hands, you're not responsible for that, I highly doubt you using your internet, or your electricity, the gas to cook up your meals or using the shower is what it is actually destroying our world.
What you're feeling is not wrong, in fact it is totally valid, it also comes from a sense of inferiority and insatisfaction in a very saturated field, pushed by the pressure of a society that constantly demands you to do more and better, because nothing is enough and nothing has no longer value except in numbers. It demands you to be an overachiever yet treats you like a parasyte, yet, we know that the ones that consume resources the most are those with power, the ones "investing", the ones "going to war", the ones "in charge" and sadly, or at least how it is in my country, in order to achieve such a big position you kind of have to get your hands dirty, become corrupt yourself... but when you reach said "top" then, maybe there's nothing left from the original you either and so the cycle repeats.
There is always an incident going on in the World that'll make humanity back down and slow down the damage or restore certain resources, sometimes at big or small scale, another Dark Age or the collapse of the Bronze age could happen for all I know or simply humanity as a collective in the very overpopulated countries or where not even the sun reaches thanks to pollution could do something, but personally, I have no control over those places nor it's citizens, there isn't much I can do from Argentina to, idk China...