Bayern Munich are not actually 4 points behind they are essentially 1 point behind because they have played 1 match less than Leverkusen. But they got themselves a win and this is what matters for Leverkusen now. Leverkusen with this victory are now 26 games undefeated and the only undefeated in Europe's top leagues.
But only 16 matches have been played, and it is too early to say by just seeing Leverkusen winning match, they are going to be the Champions of Bundesliga. So I am going to disagree with @boltz . There are still 18 more matches left, and If I had to say which game would decide the champions of Bundesliga, I would say that would be the match between Bayern Munich and Bayer Leverkusen in February of 2024.
Technically it remains 4 points and cannot be said to be 1 point even though they still have 1 match left to play because after all we cannot make it a reference to 3 points because the possibility is that they cannot get full points in the matches they have not played even though their probability is great.
But for the problem of Leverkusen's victory this season I don't think it can be used as a belief now because after all I agree that the matches in this season are still very long and to say the champion of course there are still many steep roads that Leverkusen must pass.
We know last season alone before the last match there were a lot of hopes with Dortmund because they only had to complete 3 points in the last match but it ended in failure especially now with the situation that the season is still very long so it would be silly to immediately say with confidence that Leverkusen won this season.