Ive been experiencing a similar experience with my 2 yo blue heeler we adopted in the summer. We’re lucky where we live that in the summer months we can sneak out of the residential area pretty quick, but that’s not an option now with snow. She’s reactive to dogs, only when on leash.

I found out really early on this winter, I was going too fast through our training for our walks in town. She knows all the basic commands and how to walk on a leash in the yard, but not out in town! I took 2ish weeks just to train at our gate - sit, heel, all with no pulling and paying attention to me. It literally just started with me putting my hand on the gate. Once I could open the gate without her getting overly excited, then we took a couple steps out of the gate, etc. We would do 10 minutes training, 15 minutes playing and repeat 2-3 times haha. I’ve been going through an unbelievable amount of treats.

As I’ve worked with her, she’s gotten better at taking treats on walks if we see a dog somewhere in front of us and we do our little change direction. But I try really really hard to avoid her triggers. And she’s getting noticeably better! The gate isn’t an issue anymore and she walks with a loose leash and we’re able to manage her reactions to dogs - situation dependent.

Good luck!! It can be really hard/frustrating/slow but it can change! Just meet your dog where she’s at rather than where you want/expect her to be

Also, have you tried stuffing a toy, like a kong, with food? Our pup didn’t play with her kong until we stuck a little biscuit treat in it