Bayern remained strong and strong even though they faltered for several weeks, due to the crisis of a center striker. although Nagelsmann had to always rotate his players, he was able to bring Die Bayern out of the center forward crisis, Choupo Moting was the answer to Bayern's need for a pure striker position.
As for Niclas Füllkrug, Bayern Munich are considering the possibility of bringing him from Wender Bremen to the Allianz Arena to find a replacement for Choupo Moting, whose contract is reportedly set to expire this season. Füllkrug is only a ready-made replacement option and capable of occupying the No 9 position, Niclas Füllkrug only fills the void in the reserve striker situation in the coming months before looking for a high-quality striker at the end of this season. Füllkrug may arrive in the summer if there is no breakthrough in negotiations with Choupo Moting before the season ends.
So, I guess the situation is not as you say.
I agree that they had a problem when they first started because their tactic and formation required a good striker and when they lacked that player, they missed so many chances. Not like they didn't shoot, they shot the ball very well and hit the goal many times as well but they were not used to asking the players the players that shot the ball this season to shoot it last year, which caused a bit of unexpected results and angles for those shots.
They got used to it a bit more later on, and now they are playing a lot better, they would be still far better if they had Lewandowski, it would have been epic to have Mane and Lewa together, but that's fine now I guess.