Help - aggression growing by the day

Hi all, Ive turned to this forum to see if I can get advice . I have a beautiful 10 month old female. When we got her the breeder highlighted that whilst she was the smallest she was the dominant female.

She’s been great albeit a tyrannosaurus during teething…. Perhaps a couple months ago we noticed she would growl if anyone looked at her or approached when eating. She then began doing it when someone picked her up for final wee.

It’s then increased so if she’s sat on her blanket or has a cushion near her of someone goes to move it she’ll lunge and bite. I know this is resource guarding and we began to put steps in place such as hand feeding and more verbal instruction instead of physical … but it’s got worse. Sometime her eyes will simply glaze over, pupils dilated .. she’ll then bear her teeth. I will attempt to remove whatever it is she’s guarding (wearing gloves because she will 100% longer and bite repeatedly). Once removed I’ll ask her to sit and she will, her eyes go back to normal.

A couple of times I’ve walked past a room she’s in on her own and she’s simply standing in the middle of the room staring at the door, like a guard dog.

I’m worried that she will attack my kids. I’m away with work today and my wife called tonight to say today was the worst day - she was guarding something today and my wife removed it, she lunged and bit her.. but once removed she continued to stare at my wife and then leapt off the sofa and lunged at her twice…

It’s very very strange. Nothing major has happened to cause a big change in behaviour . She is exercised appropriately, has good interaction with a family of 5 kids aged 16,14,10. We are all confident and I for one present in a calm dominant manner without physically hurting or shouting at her.

My worry is that this is something inherently wrong which will worsen and my family or visitors are in danger. She is a beautiful loving dog and most of the time is tail wagging, playing etc etc…

I am going to take her to the vet initially but does anyone have any experience of this and what did you do?

Thanks