They are not doing great. They exited the cup against a third league team, which is a disaster, and they so far played a pretty terrible CL season (for their standards). Nonetheless they are getting better results in the league than last year and on a level that absolutely would win them the title in almost every year.
Alonso's Leverkusen just equalled Bayern's record for the most unbeaten games of a German team in all competitions in a row (31, previously held by Flick's sextuple winning Bayern alone - although it's BL, CL, Cup for Flick and "only" BL, EL, Cup for Alonso). That's really not Tuchel's fault