I, personally, think that Effective Altruism is bonkers.
Back in university the philosophy was the only course that I ever failed. This has shaped me profoundly, as I started to read a lot more and to this day think that Karl Popper is a much more important figure for the modern science than Newton or Einstein. I also eventually married a philosopher. And from the point of view of a person that knows anything about philosophy: Effective Altruism is pure garbage.
Its ethical system is pure utilitarianism, which I never liked. Its reasoning about value and virtue is executed in "constant prices" and ignores economics (both classical and behavioural branches).
The core tenet is maximizing the humanity benefit across space and time by trying to price the future benefits in current prices. It is crazy.
There is an old joke: If you did not have a bicycle as a child, you can buy the most fancy car as an adult - but you still did not have a bicycle as a child.
This applies to their approach to charity. Their aim is to earn as much money possible during their working life (including by scams, fraud and crime) to then give it all to the charity at the end of the life. The reasoning is that a banker with millions of dollars to give is more beneficial to the society than a school teacher with mere hundreds to donate. But this arguments falls flat if one imagines what happens if Effective Altruism becomes a dominating system of beliefs. In that case a banker that scammed his way into a billion dollars would reach out to a young doctor to administer life-saving vaccines, but the young doctor is also following EA and their goal is to maximize their lifetime's money pool to give out at the end of their life. So the young doctor will charge the banker exactly one billion dollars - the banker's entire lifetime charity pool - for a single vaccination. Why would not they? They are only being rational. And when that doctor retires with a trillion dollars and is looking to donate to a young researcher curing cancer, the researcher following EA will charge a trillion for a single test. The Effective Altruism model of charity can only work if there are people around who are not following it, who are willing to give up their working hours and earning potential to give a child a bicycle now, instead of a Lamborghini in 30 years. If Effective Altruism becomes the dominating system, then all of the charity work stops and nobody is saving babies drowning in shallow pools.
Have you noticed that I used Categorical Imperative by no other than Immanuel Kant to easily defeat the core tenet of the Effective Altruism? It is not because I am smart, it is only because I am educated. Decades since I failed the philosophy course and had to retake it I am immensely grateful that it was not optional for my degree. I wish more people getting Computer Science degrees in "top" US universities would've had that requirement as well.
Studying philosophy will not give you the answer to what the best ethics system is. But it will shield you from the evil ones, constructed by uneducated dimwits in their parents' basements.
I think reading Karl Jaspers, Karl Popper, Immanuel Kant and Gottfried Wilhelm Leibniz should be mandatory for anyone attempting to construct an ethical system. It is probably not a coincidence that all four were writing in German. And it is probably not a coincidence that the last German-language post on Effective Altruism forum is from four years ago and the last update on the German EA site is from almost two years ago. Hmm... Should I have added Albert Schweitzer to the list?