My dog goes absolutely nuts when she sees other dogs on leash

i have a 2 year old shepherd mix named Nova and she is the sweetest dog at home - cuddly, calm, great with my kids. but the second we're on a walk and she spots another dog, it's like a switch flips. she lunges, barks, does this shrieking howl thing, and doesn't stop until the other dog is out of sight. it's embarrassing and honestly a little scary even though she's never actually hurt anything.

we adopted her 8 months ago and she was like this from day one. the rescue said she "preferred to be an only dog" which i'm now understanding was a polite way of saying she has leash reactivity. we've tried walking on the other side of the street, we've tried treats (she's too worked up to eat anything once she spots a dog), we've tried the "watch me" command but she won't look at me at all once she's locked on.

i really want to fix this because i love taking her on walks but right now every single walk is stressful for both of us. do i need a professional trainer? is this something people actually solve? or is this just... who she is now?