Is there a reason other than naked greed, why you (philosophical 'you', not you personally) would raise your prices accordingly? Keep in mind that even as a multi-millionaire slumlord you would also receive UBI (or else it ain't universal) which is enough to cover basic food and shelter.

Because you don't directly set real estate prices based on the buyer's income. You simply sell to the highest bidder. The bidders look at their own income and decide what to pay. If all the bidders have more money, the price will tend to rise.

The prices will rise without fail, as seen in every real estate market from Shanghai and Toronto to London and the San Francisco Bay area.