I learned the 'European methods' of working dog training in my early years, and now reading the articles and seeing the videos of your methods of dog training, I need help in how to fix the bond damage caused by them. How can I correct/mend/repair my relationship with the dogs?

I learned the "European methods" of working dog training in my early years, and now reading the articles and seeing the videos of your methods of dog training, I need help in how to fix the bond damage caused by them. I had learned from trainers I observed to use the leash end as a whip. If the dog doesn't respond to a command, you issue a "correction" lash to their behind and then repeat the command. I respected these trainers and they had great dogs, and even though I didn't like this method, I followed their advice. I never beat them repeatedly, just 1 correction like they told me. this has done more bad than good to my dogs. I have obviously stopped and now using your methods. But how can I correct/mend/repair my relationship with the dogs? They are now shy dogs, and without that bond they will never reach their true potential; Are they ruined? or is there something I as a handler can do to bring us back as a team? thank you for all the help you can give.