After the 14-day trial, if you love it, pay the $19.95. That is the cost of two Starbucks coffees. It supports a small developer team.
Go to the official Letasoft website. They offer a fully functional 14-day trial. No patcher needed. Test if it actually solves your volume issue. patcher letasoft sound booster better
Right-click the speaker icon > "Open Volume Mixer." Ensure no individual app is turned down. Then, try the "Loudness Equalization" trick from Alternative 3 above. After the 14-day trial, if you love it, pay the $19