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It will be probably hard for Audi at least in the 1st year.
If' I'm not mistaken they will use their own engine and it will requires time for innovation.
The good thing about it is that they will can boost the progress with frequents updates.
Same thing will be for Redbull, they will build their or own engine from 2026, without the (official) support from Honda.
If I'm not mistaken, which I could easily do so, and if we exclude Brawn GP, which was basically Honda, no team has this century won a race on their debut year, cause the the 60s Fangio era were wild, so you can't really count that.
So, using history,a normal Audi will not be able to score a victory, if it does so,it would be the first team to do so, making history.
Same story with Cadillac.
I'm too bored to check the data and not going to ask some chatbot to do so, but I don't think that any team managed to win the championship even in the 3rd year, forget the first.