I wouldn't worry about the extra features. Most of the ones you've listed are used to clean up bad recordings, but that's something you're in control of here.

For recording, the software doesn't matter much. The most important thing IMO is to record at a level where the typical amplitude of the input audio (normal speech in this case) sits at around half the max level of the input. That's because you can always increase the volume level after recording, but once a loud segment clips above the max level, that distortion is there forever. Recording in 24-bit vs 16-bit helps with this strategy, because the extra bit depth in recording amplitude resolution allows the headroom to boost the volume later without any perceptible loss. Large diaphragm mics sound best for voice recording. Of course, I'm not recommending you run out and buy a large diaphragm USB mic that can record in 24-bit if it's prohibitively expensive. I don't know what your setup is currently, and for most listeners, good mastering will make a bigger difference than great recording gear.

Stereo Tool can make almost anything shine, but if that's too pricey as well, just find a post processing tool with a good compressor/limiter combo and an expander. There are probably good open source tools out there.