We have all been there. I have had one belt, a chest and a forearm crack or snap in half. I used the same repairs you are using and even tried to use PLA and a soder iron to weld. In every case they just slowed the inevitable break. I bought new pieces and reinforced each one with ABS glued to the back for support to help give it some structure. My belt and chest cracked and broke due to having it too tight. I now use hidden velcro, snaps, and magnets to hold the items where I want them and keep the straps loose to allow some give for movement. It is very fraustrating, but don't let it discourage. The scouts one of the best and iconic outfits in Star Wars.