This won't be a fun way to play buuuuuut you could assign someone (or AI) as the banker's friend, who receives double the money or the ability to borrow at 0.1%.

1/ They'll either out-bid or buy all the properties - game over

2/ Borrow money to pay their way out of tax, could add a rule that makes the cost of servicing hotels more expensive so eventually the non-banker friends won't be able to afford the upkeep

3/ Borrowing increases the income tax (banker's friend exempt due to off-shore accounts)

4/ The banker's friend can use existing properties as collateral for future purchases.

I imagine the game will be over very quickly, so in round 2, non-banker players will have BTC, and its purchasing power doubles every trip around the board, some shit like that :)