Bayern will not sack Tuchel during the season. The club wants more continuity after the time of Flick and Nagelsmann. The only goal that has not been achieved so far is that they have not reached the cup quarter-finals. In the championship they are 2 points behind Leverkusen and in the CL in the round of 16 against Lazio. There are currently no reasons at all and no rumors about a possible dismissal.
It depends on the president of Bayern Munich. If he is satisfied to finish at the second position, he must keep Tuchel as Bayern Munich coach. I think it is not so bad achievement if Bayern Munich finishes the season at 2nd place in Bundesliga. Moreover, if Bayern Munich can continue the UCL match until the semi-final, it is also quite good for Bayern Munich.
I would agree to that. Second place would certainly be painful for Bayern and after winning the championship last year by a wafer-thin margin, it would certainly be a reason for the president and management to think about Tuchel. The only question is who should succeed him. Bayern always need a special type of coach and there is currently no one on the market. The only one I can think of would be Klopp, but he wants to take some time off and he probably won't want to get back into club football so soon.