Here is how we run delta sync as a PS command in adaxes. We "remotely" run it on any domain controller server. Your adaxes server must have visability to domain contoller of course.
We have it run after user creation and have it as a manual push button action in the web home page for my techs. We had to take it off user modify, because when we would export CSV info nightly to our users it would spam the delta sync and MS would block us.
$dirsyncServer = "srv-001.ourdomain.local" # TODO: modify me
Invoke-Command -ComputerName $dirsyncServer -ErrorAction Stop -ScriptBlock {
Import-Module "C:\Program Files\Microsoft Azure AD Sync\Bin\ADSync\ADSync.psd1"
Start-ADSyncSyncCycle -PolicyType Delta
}