The installer and uninstaller are an NSIS package:

"OBS-Studio-27.0.1-Full-Installer-x64.exe" /S

Uninstall:

'C:\Program Files\obs-studio\uninstall.exe' /S

I found 2 gotchas with the uninstaller:

1.  The uninstall process tends to complete but not exit, but only when called by SCCM.  I added this to the PSADT script in the Post-Install section:

$UninstallApp = Get-Process Deploy-Application -ErrorAction SilentlyContinue

                    if ($UninstallApp) {$UninstallApp | Stop-Process -Force}

2.  The uninstaller also leaves C:\Program Files\obs-studio behind:

$obsfolder = 'C:\Program Files\obs-studio'

            if (Test-Path $obsfolder)

                {Remove-Item $obsfolder -Recurse}