dnd 5th – What difficulties would a character encounter if he tried to take Amphail as a protectorate?

In Storm King & # 39; s Thunder, our group visited Amphail and found it badly damaged by marauding giants. There was an NPC (a minor noble) who was visiting after the attacks and he was advancing the money of the inhabitants for them to rebuild their homes and businesses in exchange for the sale of the land that s & # 39; They found there.

With the wealth accumulated by my character, he could have offered a counter-offer on a number of them (but probably not all) and essentially buy a large part of the city.

I chose not to let my character pursue this because it would probably have been a big distraction from the main quest line. But if I had, what kind of difficulty would my character have encountered (from a historical point of view).

I read on the Wiki Forgotten Realms that:

Guards of the water [patrol Ampahil] from Rassalantar.

But it's not clear to me that a benevolent takeover of Amphail would necessarily put my character in conflict with water lords. Am I wrong? Is there another problem (non logistical) that I miss?