The single biggest flaw of solo heavy bag training is that the bag doesn't hit back. When there is no physical consequence for dropping your hands or standing completely square, your brain subconsciously stops dedicating resources to defense.
This is how fighters develop beautiful, powerful striking combinations that leave them completely exposed to a counter-hook.
You have to force your brain to react defensively. If you are shadow boxing, you need an external trigger to tell you when a strike is coming. This is why a digital pad-holder app is practically mandatory for solo work.
In Shot Caller Nak Muay, defense is baked into the combat algorithm. The app doesn't just call out punches; it regularly commands defensive actions mid-combo.
If the app tells you to check, do not ignore it. Your goal is to map the audio cue to your muscles instantly. By reacting to random defensive callouts on the bag, you wire your brain to keep your guard active when returning to sparring.