Every professional installer (either for the home or the studio) measures, tweaks, measures, listens, and gets it right.
Every Joe Six pack like you that slings money at the problem at Best Buy couldn’t hear the difference anyway. Don’t walk away angry, it’s not my fault you have a blow torch at your wallet and another one you have to sit on every time you turn on your system.
I realize you struggle just using your phone, here get professional help, you can thank me later:
https://homeacoustics.org/haa-training/