Finding SiteFields with not term set and fixing it.

[Ofer-Gal]

We provision new sites with site design in Logic App. Most sites turn out fine but few sites every now and then, do not have the connection to the term group and term set.
Should show like so:

But shows like so:

Then users can't select any term on the inheriting fields.
We want to run a fixer script every night to find these missing associations and add them.

Can anyone figure out a PnP.Powershell to find fields with no term set and then add it.

Appreciate the help
I found out I can find the bad ones with:

		$DocTypeField = Get-PnPField -Identity "DocumentType"  
            if (-not $DocTypeField.IsTermSetValid) {
                #This is one that does not show the document type term set selected. but it contains the same TermSetId as the good ones
            }

But I can't find a "Set-PnPTaxonomyField" commandlet only "Add-PnPTaxonomyField" which will add a column field not replace it.
Is there a property I can change to make it Valid?
Set-PnPField ? maybe? what will the value be then?