The following seems to work
If (Test-Path Alias:wget) {Remove-Item Alias:wget}
If (Test-Path Alias:wget) {Remove-Item Alias:wget}
wget
The first line removes the Script level alias, and the second removes the Global level alias. Note that both need to be tested, because if the Global doesn’t exist the Script isn’t created.
Also this misbehaves in that it modifies the parent without being dot sourced.
Alternatively you can just dot source your original and that would work
. .\wget.ps1