These are some recommendations of private accommodation booking.
General:
Hostels:
https://www.aohostels.com/de/muenchen/
https://www.wombats-hostels.com/munich/
https://www.euro-youth-hotel.de/
Hotels:
https://www.meininger-hotels.com/de/hotels/muenchen/
https://ibis.accor.com/de/city/hotels-munchen-v2729.shtml
https://www.motel-one.com/de/hotels/muenchen/
Apartments:
https://www.apartmentservice.de/en/apartments/living-hotel-am-deutschen-museum.532/
https://www.joyn-living.com/en/cities/serviced-apartments-munich/
https://apartmenthaus-international.de/home_en.html