Leverkusen is doing wonderfully. Their overwhelming dominance in most games and unbelievable number of goals are amazing. Although Bayern usually wins the Bundesliga, this is a nice change. With a four-point lead over Bayern, Leverkusen fans are excited about the possibility of a title comeback.
Bayern Leverkusen only has a shot of winning the league if they are consistent, they four points difference doesn't matter if they can't keep on winning we know that because every season bayern usually have their ups and downs but there have not been any consistency from any of their previous league title contenders.
Nevertheless, we must deal with problems in the future. Bayern may have a deeper roster than Leverkusen, and playing in both German and European tournaments may be hard on the players. If this happens, it could wear down important players, making them less effective in important games. To get the title, Leverkusen may need to rotate their team on purpose and put more emphasis on the Bundesliga over other events. After making sure everything is balanced, a new Bundesliga winner might be born this season.
You seem to forget that Leverkusen is also in the European tournament though their's is a lower tier but that doesn't mean it won't be tasking and challenging for them even Liverpool who sometimes try to rest their main players in the Europa league still fail to win using this method and this shows the competitiveness of the Europa league this season