If you actually want to know what the best movies are, then the Oscars is probably not the best way to get that information. First of all, it's extremely US based(understandably), even with it's foreign section. Second, it's all just a show anyway, so they want a lot of people paying attention to it. That's usually not the best indication of quality.
Oscar has the qualifications for the films selected to be nominated, even though its base only covers the United States but there are other requirements for films to be nominated, so I think films that have been nominated for Oscar are one of the best films, while indications of quality need not be doubted because they have the conditions to be included in the nomination.
From the several revenue tracks that I see on social media, many film industries hope to be included in the nominations made by the Oscars, which means that the credibility of the Oscars cannot be doubted.
Things like movie forums or specialized magazines, etc, would probably be a better source of information to get to know the best movies.
There are many other ways to get to know the best films made by the film industry, not only in the nominations made by the Oscars and I think everyone must be different in seeing the best films because not everyone's taste is the same.