I'd investigate Armillaria, aka honey fungus. It's common in FL and ligustrums are prone and the decline looks pretty much like your photos and as you describe. Your county extension service should be able to confirm for you.

If it is armillaria, then they do need to be pulled and destroyed. It is eventually fatal and there is no cure. And you need to select an armillaria-resistant plant if you wish to replace.

Thankyou I'm going to look into that!

if you rule it out ... most likely you could cut them down to about 3 to 6 inches ... and if they have a healthy root mass ... by end of spring.. you might be surprised how big they can get ...

the search term is rejuvenation pruning

https://duckduckgo.com/?q=rejuvenation+pruning+privet&t=ffcm&iax=videos&ia=videos

privet is usually a run it over with the truck kind of plant ... so dont think you can kill a healthy one by hard pruning ...

but to repeat.. you have to rule out the issue gal raised ...

ken

Thank you so much Ken! I am hoping to get confirmed but it has all the tell-tale signs unfortunately. We have more of the same plant in another part of the yard so I may prune those.