Olympiastadion from Munich is good for both 2. Bundesliga and 1. Bundesliga (and yes I know it is planned to be renovated between 2024 and 2027). I would say that for now that is the only feasible solution for 1860 Munich as the Grünwalder Stadion is definitely not good for 1. Bundesliga (and it is not 100% sure when they will renovate it, if after 2027). Grünwalder Stadion is also limited for expanding its capacity to a maximum of 18.500 seats, that is only 3.500 more than what is having now.