Actually they really have to find a replacement for Manuel Neuer, I mean Neuer will definitely be replaced, but with what he is experiencing now, Bayern Munich has to look for it faster than it should. There are several names that are being targeted by Bayern Munich, and those names are goalkeepers who performed well during the Qatar World Cup. Croatia goalkeeper, Morocco goalkeeper is one of the many names that are now their target players. I'm sure they will get the goalkeeper they are hoping for in the transfer window.
After Sadio Mané injury another big setback for the Bayern Munich as they lost heir first priority goalkeeper with mostly he will join again after in next season and Bayern Munich is having their top rank back after tough fight, so things are looking not easy for them with now they are going to face PSG in knock out round as well hopefully they will be able to have suitable replacement in January transfer window which will help them for having better performance.
Now they have few good options like Moroccan goalkeeper and few others like Croatia, hopefully Bayern Munich management will be able to have quick approach for them and bring quality replacement because now things are not easy, and they have to give their best for this spot as well.