I will try...

Vaccines are studied by researchers from different affiliations, and published in peer-reviewed journals. Such studies require multiple stages, and when a vaccine is considered ready for the public, its side effects are already known.

Big pharma is corrupt, but their main goal is money, and they get A LOT of money from selling vaccines. In the unlikely event of one company frauding a vaccine, this would be such a scandal that would affect its commercial relations in the entire world, thus, generating less profit in the long run and making investors move to other companies.

The government is corrupt, but they want the population to be healthy enough to work, pay taxes and contribute to gdp. Giving room for simple diseases to kill people goes totally against the government's goals.

Remember, neither governments or companies want people to die, and curing lethal or disabling diseases goes in their own interests. Besides, we already have lots of chronic diseases and conditions around to continuously sell medicine.

There's no reason for any involved party to create fake vaccines and give it to people. If you're really unsure, I recommend contacting universities and asking about assessment programs ( I don't know how that would be called in english), because some places test samples from vaccines that will be used, in order to check if everything is ok. They probably publish the results too, and they're not only experts in the field, but are independent parties.

I hope this was of some help.

You're talking in such broad strokes that it'd take an entire essay to dissect what you're saying.

In short, there are areas of government and industry where corruption is a problem and others where it's not, and yet regulation is still the norm. You frame it like it's not that way at all and structure your argument around that. The reality is more complex with many other actors:

we're supposed to believe they have our best interest in mind?

Yes. Neither big pharma nor the government are calling the shots all on their own. It's not just business at play but public health along with the entire field of medicine and the research body. You're completely ignoring the history of medicine and how it has shaped our global health sector.

Epidemiologists around the world have been warning us about pandemics for decades, especially about coronaviruses since SARS hit Asia. These viruses are ancient and their potential is well studied. Only their mechanisms of infection are new.

Like, why now?

Because evolution happened right in front of our eyes and we happened to have a technology ready for it. mRNA vaccines have been 30 years in the making. Shit happened and we were the lucky winners. This is how history goes.

Why am I supposed to trust that what they say is safe and effective is actually that?

Because of science. Big effort is put into this by independent bodies by microbiologist, pharmacists, geneticists/molecular biologists, chemists, immunologists, etc. advancing their individual careers. Countless hours of labor has gone into making the technology possible and also painstakingly understanding the microbiology that makes it all possible. I think this arguably and easily goes back to the 70s. It's not new and it's not just one group behind this, even if only three people got the Nobel Prize for it within the last year.

drugs that have been used and studied for decades have been pulled of the shelf because it turns out it does more harm than good

Yes, and also many hundreds of others have endured and will continue to be safe within reason. The list of essential medications is incredibly long.

As the saying goes, "if it can't harm you, it can't cure you," because it means it doesn't interact with your body in any way.

The reasons for pulling drugs out of stores are incredibly varied and you can't just dump them all into one bucket.

One of those reasons is human error, another is uncertainty and yet another is lack of knowledge, among so many others. Not everything is a conspiracy.

Instead, be grateful that our pharmacovigillance is working and that safer drugs are being made with new tech, like the mRNA vaccines.

the covid vaccine isn't nearly as effective

Because of evolution. It's an evolutionary arms race against a virus with a short mutation cycle that branches off into variants quicker than we can adjust our drugs. If the virus didn't change, it'd have been exterminated the first year of the vaccines.

Please let me know if I need to clarify, correct or expand on anything above. I'm happy to provide credible sources where needed.

healthy people buy medicine to stay healthy.

Dead people do not.