Do you have an air conditioner running? I show a background roaring sound like a fan or air handler. It could also be your computer fans.
I got your clip to pass ACX Conformance in Audacity 2.1.3.
I followed the basic ACX Mastering Suite, version 4.
https://forum.audacityteam.org/t/audiobook-mastering-version-4/45908/1
But I had to follow it with noise reduction of the beast (6, 6, 6).
The two seconds of silent room tone is harder than it looks. I show shuffling or maybe furniture sounds in about the 0.6 second mark and a gasp for air at 1.7 seconds. That’s important because Effect > Noise Reduction needs that pure room tone to work and so does ACX. They have requirements for room tone in their submissions.
In my opinion, your voice is a little too sharp and harsh. Your real voice is probably fine, but the system is pushing it to be too bright. That would indicate Effect > De-Esser, but let’s get the basic recording to work first.
Your basic reading is fine. You have a problem I had recently. Trying to read something too long for one breath. Extended exposition and digressions are not welcome when you’re trying to read out loud.
Koz