Powershell / Chrome Selenium - Forcing update of default download directory

Question

I have been trying out some automation using Powershell and Selenium + Chrome, however I am struggling to be able to have the default download folder actually apply when Chrome is launched.

I have used this as a guide to set the default download directory in Powershell, and while it does boot launch Chrome with the directory set in "chrome://settings/?search=download", it isn't actually applied (unless you manually press the 'Change' button in settings, which defeats the point of automating it!) and still download to the default user downloads folder:

Chrome settings after PS launch

#WebDriver.dll - C# 4.10 - .NET 4.8
#ChromeDriver - 97.0.4692.71 

$WorkingPath = 'C:\PSChromeSelenium'
[System.Reflection.Assembly]::LoadFrom("$($workingPath)\WebDriver.dll")

$ChromeOptions = New-Object OpenQA.Selenium.Chrome.ChromeOptions

$SavePath="C:\Temp"
$HashTable = @{}
$HashTable.Add("prompt_for_download", $true)
$HashTable.Add("default_directory", $SavePath)

$ChromeOptions.AddUserProfilePreference("download", $HashTable)

$ChromeDriver = New-Object OpenQA.Selenium.Chrome.ChromeDriver($ChromeOptions)

Downloading using 'Save / Save As' still opens to the default folder.

Any help would be appreciated! Thanks in advance.