Could you elaborate more?
> mRNA vaccines tell our cells to make a piece of the “spike protein” that is found on the surface of the SARS-CoV-2 virus. Since only part of the protein is made, it does not harm the vaccine recipient, but it is antigenic and thus stimulates the immune system to make antibodies.
Additionally, one of the studies referenced in the linked paper also states that negative thromboembolic events are observed in vector-based vaccines but are absent in mRNA vaccines:
> Here, we present first molecular evidence that vector-based vaccines encoding the Spike protein exhibit a problem that is completely absent in mRNA-based vaccines. This is due to the fact that during the vaccination step, the adenoviral DNA enters the nucleus and use the host machinery to transcribe its (trans)genes inside the nucleus.
Even though I dont have the expertise to decipher this scientific paper, from my negative experience your concerns are absolutely valid.
I don’t understand why people are so quick to downvote
Why people would just immediately attack the vaccine and not discuss the fact that hundreds of millions, eventually billions of will be exposed to way higher levels of spike protein through actual infection is beyond me.
I agree that it's not ideal, but what was the alternatives?
Let it go wild, destroy the economy, let hospitals collapse?
Why can't there just be a better vaccine. What incentive do pharma companies even have to make a better vaccine, rather than one that is just "good enough" to be shipped as a product to a ready, desperate market.
For example, Varicella is 85% effective against any infecttion and approx 100% against severe infection. . Polio is about 90% with 2 doses.  Influenza vaccines sit at about 40-60%. 
Of course, it's also important to point out that they are improving them. Work is already underway to produce vaccines targetting the Delta strain more directly, in an effort to resolve some of the effectiveness loss that gen1 vaccines have against it. Indeed, this is one of the major advantages of mRNA vaccines - the iteration time from new design to new drug is a matter of weeks, so overall iteration for boosters is similarly shortened. This is extremely attractive for use against influenza and coronavirus which mutate fairly rapidly.
The incentive for pharma groups to do this is twofold: 1) the US/UK and other similarly vaccinated populations will want boosters and will pay for them, and 2) that the vaccine status outside of the US/UK is radically different, with most countries barely scraping 10-20% of their population vaccinated. There's still a lot of people needing vaccines.
There is certainly an incentive to make a mostly safe and effective vaccine, but what incentive is there to make the best one possible? Especially when they are given complete indemnity for their decisions, and walking through preopened gates of government approvals. I feel there is a big moral hazard here that we just hand-wave away.
A better vaccine is currently not a reality, it doesn't exist, it's not readily available.
Why the false dichotomy that only big pharma can do research and produce something?
I was under the impression that mrna vaccines relied on the fact that spike was the harmless key. As such wouldn't it make sense if the doses were designed to be quite high ?
Another question ( in case any specialist read this) : wouldn't it be possible that the S protein alone, being smaller than the whole virus, and being generated from unusual locations, is able to reach cells that would usually be protected in case of a regular airborne infection ?
Regarding location, it's more of an issue in the opposite direction: the fact that it is delivered through intramuscular injection gives a slower and poorer immune response in the mucosa, the first line of defense, compared to hypothetical, equivalent vaccines administered orally or nasally. Currently you have to rely on antibodies getting to the mucosa through your blood. We know that the virus can reach the brain, the GI system, etc., so there doesn't seem to be "total" protection. Of course, across different people and different immune responses, there's going to be a variable amount of viral proteins hitting throughout one's body.
I guess the prevailing wisdom is that the dose makes the poison and a little bit of spike protein damage is acceptable compared to a much bigger amount from actual infection and disease.