The whole code for setUpTable function is below along with the game scene. Thanks for showing your code. That will help understanding what is your current problem and thinking how to fix it.
As I wrote before, you need to run a code to change the background at each time playerScore changes.
There's no code to change the background in your GameScene.
You are not doing anything to change the background on playerScore changes.
(Your setupTable() is called only once when didMove(to:) is executed, not on playerScore changes.)
For adding a code to change the background, you should better define a type representing the type of the background.
enum TableType: String {
		case ovaloffice
		case austin
		case bond
}
extension TableType {
		static func `for`(score: Int) -> TableType {
				switch score {
				case 0...19:
						return .ovaloffice
				case 20...29:
						return .austin
				default:
						return .bond
				}
		}
		var imageName: String {rawValue}
}
And to change the background a little bit efficiently at each time playerScore changes, you need some properties to add and modify one property.
		var tableType: TableType = .ovaloffice
		var playerScore = 0 {
				didSet(newScore) {
						let newTableType = TableType.for(score: newScore)
						//Call `replaceTable()` only on `tableType` did change
						if tableType != newTableType {
								tableType = newTableType
								replaceTable()
						}
				}
		}
		var currentTable: SKSpriteNode?
The method replaceTable() would become something like this:
		func replaceTable() {
				//You need to remove existing `table` before adding new one
				if let table = currentTable {
						table.removeFromParent()
						currentTable = nil
				}
				let table = SKSpriteNode(imageNamed: tableType.imageName)
				addChild(table)
				table.position = CGPoint(x: size.width/2, y: size.height/2)
				table.zPosition = -1
				//If you need to modify some properties based on the `tableType`, uncomment the following switch statement
				/*
				switch tableType {
				case .ovaloffice:
						//...
						break
				case .austin:
						//...
						break
				case .bond:
						//...
						break
				}
				*/
		}
You can modify your setupTable() using it:
		func setupTable() {
				replaceTable()
				addChild(moneyContainer)
				moneyContainer.anchorPoint = CGPoint(x:0, y:0)
				//...
		}
The code above is not tested and I may be missing something important to show, but please try.
If you find something wrong with my code, please tell me what's going wrong in detail.
