It seems like a lot, but then consider that only 5% of people killed by police in the US were unarmed. The other 95% were armed, and most of those cases seem to be actual criminals rather than ordinary people like Breonna Taylor's boyfriend.
I'm with you on the American police being quite distinct from other police forces, and there's a lot of criticism to be made about them - like failure to keep proper statistics about police killings - but I think it's also fair to consider the circumstances that they work in.
As for your first point, many of the things can be true at the same time: US puts too many people into jails, there is too much crime in the US, and there are ways to obtain justice that are not available in most other countries (mass media, social media, courts).
You say this so casually, like the 95% of people killed deserve to be dead? Most other developed countries had problems with guns, and have dealt with it by restricting them, not by making the police militarised and just shooting more 'bad guys'
How many countries in the world do you imagine don't have courts, social media or mass media? Or even lack any of the above?
Do you have the link?
I don't know how to find the number of arrests, but in Australia there were 4 people killed by law enforcement in 2016/17 and in the US there were 1,536 killed (2019). Australia has a population of 24M, the US 329M, (so 13 times the population). At the same per-population rate as Australia, the US would kill 52 people, and at double the per-population rate it would be 104.
It would seem astonishing that the arrest rates somehow converts to the US only killing twice as many people!
So I think that makes around 125-130 unarmed people killed by police. [1] says that there were 1,134 people killed that year by police.
125/1134 = 11%
[1] https://www.theguardian.com/us-news/2015/dec/31/the-counted-...
Also that's still "only" 25% that are unarmed.