I've been able to routinely buy and sell a house for close to a million euros each time (500k profit). Unfortunately you must have a little bit of seed money to buy the house on the moon, at 402,814 euros and some change for renovation/furniture 16K should be sufficient.
Aiming for this may allow you to get
The Negotiator achievement in House Flipper worth 429 pointsSuccessfully negotiate a sale earning no less than 50,000 Euro. and
and should take between 30-45 mins depending on how quick you are.
Your aiming for Dolan Trusk who has a Room Preferences for only 1 bathroom, and bedroom, an office.
"Beside the office and corridor, the other furniture should be as cheap as possible."
Buy the House on the Moon, clean and remove all trash. Once you have done this sell the four single beds all kitchen items, store room shelves and interior doors.
Move the dining table and chairs into the old kitchen space, and move the sofas, chairs and cabinet at the end of the corridor to where dining table was. Move the office equipment into the room that had the 4 single beds. Replace all interior doors.
Place a wall and doorway into the new living room and one at the end of the corridor between the last interior door and the exterior doors this will become a small kitchen.
Divide the main corridor into 3 sections using 2 lintels one above the double doors and the other between the exterior doors and first internal door.
In the 3 corridors use expensive rugs, clocks, ceiling lights look for comments from Dolan like "rich looking" and "More More I want them to know who their dealing with".
Convert the old store room into a home library.
In the office put expensive electronic equipment, a rug, desk lamp and picture.
Put 3/4 thin tall bookshelves in every room as Dolan likes somewhere to keep his documents.
If all has gone well when you come to sell Dolan Trusk should be at the top of the list with no complaints and an offer of around 800/900K.
See below screenshot and proposed room layout.
Grateful if anyone can confirm if this works for them.
https://imgur.com/a/W9GAmFPhttps://imgur.com/a/6qysjf1https://imgur.com/a/gUuHiqn