Because the director wanted to have authentic-looking hockey in the film he chose to cast all the roles of the hockey teams and coaches with real high school and college hockey players. He felt it would be better to look for hockey players that had some natural acting ability and give them acting coaches rather than trying to train actors to play hockey.
The actor playing David actually split his eye open by playing on bike ramp during his off time and not wearing a helmet and had to get stitches right before filming the final game of the film, forcing a rewrite of the last scenes to include stitches.
The final Hockey scenes were originally shot in the first week of filming. Due to the Covid-19 shutdowns, there were about six months of waiting before the last three scenes of the movie could be filmed. During that time the main actor who played the role of David grew more than six inches. Because there was such a drastic change in height the last half of the movie along with the final end hockey game had to be completely re-filmed.
The "mean girls" in the film are played by some of the nicest actresses the director has ever worked with. He couldn't believe that they could be so mean on film but such amazing human beings off camera.
Sophie the dog actually learned her lines for the film and did them on command, there was no CGI used for the "growl talking," she did throughout the film. It was six months of prep, animal trainers, and an amazing animal.