Step 1: Make sure you register with each hotel chain and have a rewards number/online account for booking stays. If you apply for any co-branded cards (Chase Hyatt/Marriott or Amex Hilton/Marriott), you will include your rewards number on the application so that points earned as a sign up bonus are directly deposited into your account.
Step 2: Map out your favorite hotels in the area you are staying. If it's a major brand (Marriott/Hilton/Hyatt) you can design a card/sign up bonus strategy around those hotels. Otherwise, look to the Ultimate Rewards portal to see if your chosen hotel is offered and then consider getting the CSR for 1.5x redemption rates or CSP for 1.25x redemption rates.
At 3/24, you should try to maximize the number of business cards you get before crossing over. You could also consider subsidizing your flight to Germany with airline miles instead of just focus on hotels. Also, although the transfer rates are bad, some airlines will allow transfers to hotel points (if you're just short of a redemption goal). If you can hit the larger minimum spending requirements, Amex business charge cards that offer Membership Rewards would be great for transferring to airlines that fly internationally. Amex MR can also transfer to Hilton at 2:1 or 3:1 during a promotion. The Resy Gold card offer (
https://resy.com/amex-offers?date=2021-08-17&seats=2) of 60,000 MR and $250 cash back on restaurant purchases for $4,000 spend is one of the best bang for your buck offers out there. The Platinum offer is great too, but has a higher spend and you would need to maximize the credits to offset the higher annual fee.
