UEFA is not done with the punishment, they are still doing their investigation which according to news will last up to 3 weeks before the investigations will be concluded, so the full punishment will be known when the full investigations are complete. This particular suspension is just to maintain normalcy in the upcoming match. Like Vinicius said in the statement he released after the incident happened, he said racists are cowards and I kind of agree with him. When the full investigations are completed I will be more than happy to hear the level of his sanctions.
UEFA is not doing enough efforts to stop such situations from happening. Many known players were victims of racism and slurs on them and their families. Zidane famous incident, Umtiti, Balotelli, Maignan and many others faced such situations at a point automatic forfeit was suggested and sanctions were done but their effect is not palpable. Fining the team or the player is not a solution. Firing him for a game or two is not a solution. I am talking about more severe sanctions, even firing him for 3 years or more or indefinitely if it was repeated once again.
By Zidane's famous incident are you talking about the headbutt? There was no racism involved, Materazzi "just" insulted his family. Could have he avoid it? Sure, but it's football, they offend each other all the time, if the referee has to suspend the game every time someone insults another player they would never play. Racism is a completely different thing.
Regarding Prestianni's case the case is still open and I'm not sure how they can actually prove anything because, if I recall correctly, the Argentinian was covering him mouth with his jersey so it's Vinicius' word against his. Anyway it's interesting to see how every time there is a discussion about racism Vinicius is involved. Luckily in the last years this type of episodes was extremely limited compared to the past, the only exception is Vinicius, I wonder why. I've never heard about racist comments about Rodrygo, Rudiger, Camavinga, Mendy, Mbappé, Real Madrid have plenty of Black players and yet the only one that complains all the time is just Vinicius.