Living with reactive dogs is hard, you will meet 1000's of experts who have just meet you dog and will know the "simple" way to cure them. They dont
This is so true.
Stay firm and never listen to them.
Mine isn’t so bad now but at her worst I stopped letting her off lead and I met a lady who insisted I let her off lead as she only wanted to play with hers 
Because I’m not nearly as assertive as I should be and didn’t want any trouble I stupidly did.
This lady’s dog was exceptionally sweet and gentle granted but BIG and my dog frankly, was a real bully and bitch to it.
She stared it down, lip curled at it, walked into it forcing it to give her space.
All while this poor dog was giving off calming signals.
I was so very embarrassed.
After a few minutes the poor big dog went mooching off by itself while my dog, who had behaved like a right spoilt brat, was getting praised and petted by this bloody woman who was still insisting she just wants to play!
I felt so, so bad for the poor big dog and really cross that my dog had been rewarded and praised for being an absolute bully to a dog who was very clearly communicating it wanted no trouble.
To this day that poor dog refuses to come anywhere near us.