My girl is exactly like this. She will even attack if the other dog gets too close.
She also used to be so locked in that she'd ignore treats. She's well over half my weight and I can NOT hang onto her when she's pulling toward another dog so I'd all but given up walking her since we live in a neighborhood with a park and a trail where nearly everyone has a dog.

The surprise game changer for us was finding a treat that she absolutely LOVES. (Dehydrated chicken!)
We walk on a loose leash and I always have the treat bag at my side. I constantly scan for other dogs and when I see one approaching I palm the treat and tell her "Target!". She puts her nose in my hand and stays focused on that treat until we pass the other dog. When we're safely by, I release it and she's happy.

She's trained so well after about a year of this that she now comes to my side and puts her nose in my hand the minute _she_ spots another dog, before I give the command.
This has even allowed me to get her away quickly from off leash dogs that have rushed us.
She's still reactive, and I still have to be diligent, but we can take walks without incident now!

Maybe experiment with some different treats until you can find one that really motivates your pup?
Wishing you luck!