Some say it’s possible to implement this strategy in Germany, while others claim you can't, due to regulations preventing the sale of mortgaged property before 10 years.There's a lot of confusion and misinformation, and no one seems to have solid information.This strategy is well-documented in the USA, with numerous videos on YouTube.

Vacasa and Evolve are two of the major players that could have an opportunity in that area for you to be boots on the ground.

Also Look at Jim Abbott the baseball player. 

@Scott Trench Had a deal close last month with a combination of your scenarios/players.

I think screening will be your best friend if you go this route to prevent the most headaches. 2) I'd say the biggest problem renting by room is potentially laws about unrelated persons living in same household.

It's vitally important to know who you are working with, and have the history of the players involved.

It's possible that this increase can prevent a lot of people from buying and might even force others to sell.Do not wait for your taxes to increase.

Thank you for sharing your story here to help prevent other new investors from falling into the same trap.

One partner has over 10 years of experience with 2000 Unit, and next one has about 900 units as GP, and the rest of us were first time multifamily players. 

Quote from @Gash Nookala: David has the right idea about building a team, but the most important player on that team is the property manager.