You need to download and install RMS Normalize. The older Audacity didn’t have a convenient way to set RMS (loudness).
rms-normalize.ny (810 Bytes)
I know this looks like a college class in effects and software management, but when you get it done, it’s three steps to go from raw reading to audiobook submission—assuming you read in a quiet, echo-free room and don’t make any mistakes.
All that and it sounds exactly like you with no noticeable distortion.
Effect > Equalization: Low Rolloff, length about 5000 > OK.
Effect > RMS Normalize: -20dB > OK.
Effect > Soft Limiter: -3.5dB and I don’t remember the other settings, but they were default.
That’s it. I announced into a Zoom stand-alone sound recorder, cut it to length, applied those three tools and made it past the ACX technical requirements for audiobooks—according to ACX. I submitted it. That was back when they allowed you to do that.

That wasn’t high enough, so I had to add one roll of “bathroom tissue” to the stack to get it up to mouth level.
Koz