I agree with you that Bayern Munich is the favorite to win their match against Lazio tomorrow, and Bayern Munich is at home. Since Bayern Munich is playing at home, it is not certain that Bayern Munich will win against Lazio if they do not play nice football and create chances to use and score goals. Bayern Munich should score a goal early against Lazio so that they will weaken Lazio's morale to play good football against them.
Considering that the game is taking place away, it seems likely that Bayern would have an edge and is expected to win. Numerous factors supported bayern to win the game against lazio. When we analyze the compositions of both clubs, it becomes evident that Bayern is the frontrunner to win the game. Nevertheless, it is essential to remember that surprises can occur in football. The thing that makes me confuse if bayern could not score even a single goal in the first leg. So, it must be noticeable by tuchel to change his strategy for the second leg. The fact that Bayern couldn't score in the first leg caused doubt among people regarding their performance.
In the first leg, Lazio showed a commendable performance. They displayed great energy and skill, which made it tough for their opponents to score. However, with the upcoming changes that Sarri plans to implement, it is uncertain how this will affect the team's performance. The only thing that i believe to happen soon if lazio will play fully defensive.
It will be interesting to see if the changes will positively impact Lazio and i hope they will not struggle to adjust to the new tactics. Sarri needs to take this option because bayern is still a potential threat to the previous lazio to qualify for the next round.