14 months into reactivity rehab with our rescue and i cant tell if we are doing well or stuck in a plateau, looking for honest perspective from people further along

Juno is a 2yo aussie mix we adopted at 8 months from a rural shelter. she came with bite history listed but no other details, was returned to the shelter twice before us. on leash from day one she has been reactive to other dogs at distance, lunging, barking, redirecting onto the leash when a dog passes within 30 feet or so. we started with a CBCC certified behaviorist at month 3, twice a month sessions plus a written protocol, and we have been working it consistently for 11 months at this point. i need help calibrating whether the place we are at is "normal slow progress" or "we should be further along by now."

What our setup looks like. we walk her 5 days a week in low traffic times, 6am and 8:30pm, on a 15 foot biothane line in a quiet residential neighborhood. we carry a high value treat pouch with cooked chicken and freeze dried liver. when we see a dog at distance we use the engage disengage protocol our behaviorist gave us, mark and reward eye contact back at us, manage the distance to keep her under threshold. she has a "find it" cue that helps reset. on a good day we can pass another dog at maybe 40 feet and she will glance at me for the chicken instead of fixating. that has been our reality for about 4 months now.

What i cant figure out. the 40 foot bubble has not really shrunk in those 4 months. months 3 through 10 it shrank steadily, from "cannot see a dog at any distance" to "okay at 40 feet." since february it has just sat at 40 feet. some weeks we have a setback, some weeks we have a great day, but the average is the same. our behaviorist says progress is not linear and we are doing well. i trust her but i also wonder if there is something we are missing or if 40 feet is just where this dog lives now. she is 3 in september and i had hoped we would be passing dogs on normal sidewalks by now.

So my actual questions. for people who have done long term reactivity rehab, did you also hit a multi month plateau and break through it. if yes, what changed. was it medication added, different protocol, just more time, or did the dog mature out of something specific. and for people who hit a plateau and never broke through, how did you decide that this was just the dog and adjust your life and your walks to that reality. i can keep doing what we are doing forever if that is what is needed but i want to know if we are stuck because of something fixable or stuck because this is where she is