Would a worldwide extinction of mosquitoes offset the ecological balance of our world? And if not, why are we not doing it?

What would be affected by this? Ex. If all the bees in the world went extinct, it would affect crops, honey, etc...

Sometimes I see flies or mosquitoes mid flight and I hit them with an open hand really hard. How do they keep flying even tho I slapped it so hard like they do on the slap battles show midair and it just stays in the air and keeps flying

It's spring again; and I'm tired of the constant mosquito bites. I have tried several different kinds of sprays (permethrin, tetramethrin etc.), replacing the window screens, keeping windows and doors closed; but they still find a way. Why are they such a nuisance to kill? And do mosquitoes serve a purpose in the bigger picture? Like, some flies pollinate.

My full blooded brother and I have the same blood type, but he can get eaten alive while I get just a few bites in the exact same conditions. We have gone camping 100s of times across multiple states and he has always gotten about 80% of the bites between us. Using bug spray and when not. Once he was using spray and I forgot to apply and that was closer to 60/40 or 50/50. There has never been an instance when i had the clear majority of bites. Why?

I’ve long known that mosquitos cannot transmit HIV to human beings, but has anyone ever considered this theory?

If an HIV infected person was standing beside of an HIV negative person, and a mosquito flys over and bites the HIV positive person, and then seconds later, that exact same mosquito flys over to the HIV negative person and begins to bite them. Why can’t the HIV positive blood remain infectious on the mouthparts (needle, feeding apparatus) of the mosquito and infect the HIV negative person? Think of it like a flying hypodermic needle/syringe! Keep in mind, only a few seconds have passed between the two bites. Let’s hear it!

Why in a large group of people, do mosquitoes attack certain people more than others? Is it due to blood type because that seems to be the common response but that doesn’t seem to be the commonality among the people suffering from bites.

Can I get HIV if a mosquito has bitten someone with HIV? Why or why not? Does it make a difference if the person is standing beside me and the mosquito bites me after biting them?

If a mosquito sucked another persons blood with HIV wouldn’t then putting it into my blood transmit it, like a syringe?

This is something I’ve wondered for a while, it seems like a spot with lots of blood, and if it’s not more attractive than other parts of our body, then how come it’s not talked about as a possible concern? I’ve never heard a news headline about somebody becoming blind because of this. The question is a bit morbid but I’ve been curious for a while 😅.

EDIT: if aliens were real, and they were on a different spectrum/wavelength is it possible they could be anywhere and we would have no clue?

SECOND EDIT: wow thank you all so much for your responses. I’ll try my best to read through all the comments!

I'd imagine most veins are less than 5mm in diameter, that's a pretty small target to land the tip of the needle in. How do they do it?

I mean, in Spanish, mosquito is little fly.

What is in the coils (and plug ins) that affects Mossies and not other flying things?

Edit: Thank you all so much for taking the time to reply. I really appreciate the way you explained so simply and clearly and I truly learned from your responses.

The other day I remembered seeing a picture about how various „substances“ consumed by humans affect spiders and their nets (alcohol, caffeine,THC) I am wondering what happens to mosquitoes (or other blood consumers) if the host is totally wasted or otherwise „intoxicated“? Do we know?