It's true that Serge Gnabry is more suited to playing as a winger or an attacking midfielder, to be a striker it looks like Gnabry doesn't have
a good finishing. Although I admit Serge Gnabry also often scores goals for Bayern, but if he play as a striker he will not play optimally.
Instead of Serge Gnabry it is better to put Sadio Mane as a striker if it is true that Lewandowski leaves and Bayern have not found a replacement.
But it would be even better if Bayern bought a new striker to replace Lewandowski, hence the rumors linking Bayern to Ronaldo. Because if it was
true that Bayern could bring in Ronaldo, Bayern made the right decision, because Ronaldo could indeed be a substitute for Lewandowski.
But if we look at Bayern's transfer policy, I rarely see Bayern interested in signing older players, but maybe for Ronaldo will be an exception.