Which athlete do you consider to be the best in the world?

2Catch
You just stated that he had the best car for 5 years in a row, but when analyzed, it turned out to be only 2 out of 5. Of course, the concept of "car" should include not only speed, but also reliability, tires, mechanics, etc., but

Yes, in 2000, McLaren was at least as good as Ferrari, they only lost the title due to their own stupidity.

I don't think it's about stupidity, but rather that Michael was simply faster than Mika. With almost everything else being equal, that's what decided it.

McLaren was fast, but unreliable, that's why Coulthard only competed with Schumacher until Monaco, when his car stalled on the starting lap of the warm-up, and instead of pole position, he started from the last place, and Mika also stalled on the last lap in his favorite Spain and instead of winning, he got 9th place.

Yes, he stalled, but he was leading with a solid lead on the most representative track of the championship, so Ferrari was better, but not critically. In a similar situation, but with the opposite polarity in 2000, Schumacher managed to pull through and became champion, and I won't even mention 1994.

In 2003, many teams were good, McLaren, Williams, and even Renault showed good races at times, but overall, Ferrari was still slightly better, and that slight advantage was enough for Schumacher to beat Raikkonen.

Remember better. The speed was more or less okay, but there were some problems every race, if not more often. But Williams had a period when they should have had 3-4 races in a row, but they didn't because of infighting and their own mistakes. And Schumacher took advantage of that, unlike Kimi, although there are no particular complaints about him, they had incomparably different experience. And despite all this, Schumacher would have been left without a title due to Michelin's strong advantage if nature itself hadn't taken pity and it hadn't rained in Indianapolis (he was performing poorly on that track, and in the end he won). And the Bridgestone rain tires were better, and most importantly, not worse, because with everything else being equal in the rain, Schumacher was pulling away from everyone as if they were standing still (remember Silverstone 1998), that's just his driving style and the design of the car. After all, let's not forget that another "rain man," Senna, also liked Berna's cars.

But despite all this, I don't consider him the GREATEST athlete in the world. Even in Formula 1, there are those who are not inferior to him, and if they are inferior, it is insignificantly. Fangio, Stewart, Lauda, Prost, Senna...

It's impossible to compare Fangio and Schumacher - they are from completely different eras. But I'm not particularly impressed by Prost and Senna, at least for one reason. They raced in a period when the minimum weight of the car was taken WITHOUT the driver (and now WITH the driver), it's not a fact that they were the fastest, but the fact that they were very light is a fact. Compare Senna, who was 160+ pounds and all bones, with Mansell, who was almost 190 pounds and was by no means a boy. That's why there was a 25 kg difference on board, and I don't think I need to explain what that translates to on a lap. Yes, Prost won in 1993, but he was still a good driver, and even a monkey could have tried their luck on that Williams.

although in each individual championship, I cheered for them in their rivalry with Schumacher.

Key words. It's very difficult for you to be objective.
I don't consider myself a Schumacher fan (I'm not inclined to fandom in general), but he always fought with passion, to the limit. Yes, sometimes breaking the rules, but he did it openly. Everyone talked about the team tactics at Ferrari, but almost no one talked about the fact that Irvine clearly let him pass only once - in the penultimate Grand Prix of 1997, and in return, he received an absolutely identical gift in Malaysia in 1999. Barrichello let him pass twice, and in return, he received at least four times. Mika also enjoyed no less bonuses from Dennis (if not more), but everyone remained silent and hypocritically pursed their lips.
I enjoyed watching Michael COMPETE, because does anyone like watching movies or reading books about white and fluffy bunnies or about cunning people wearing angelic masks? No, people love and hate (which is largely almost the same thing) direct and open heroes. It is these that are remembered. That's why I look at the current characters in Formula 1, and most of them don't make me happy at all.