Cool game, it is tiring, but it makes you want to play it until you can't.
Its easy not to destroy your possessions, play on roomscale away from things you can punch. If you have a 2m x 1,5m like me heres a tip.
So you don't punch your objects in your room: Set the camera to lock onto the opponent in the settings if you have a small room. This will make you stay oriented IRL. Try standing with your back not too far away from your rear boundary where the game takes you into your corner all the time. Start from there every time and you can fight without fear of damage.
If you're stuck, read the tips on the left, practice the weakpoints on the dummy, turn off the automatic punch scaling to make it easy until you get hit with the confidence that you'll whoop anyone before you and set it back. You can always customize beaten opponents or yourself.
I didn't know i had this many muscles in my back until i felt them burning :)
I don't have much time in the game so far, but i am hooked both lef and right.