Rasing input/output via amixer and saving settings

I'm using a DAC+ADC Pro on a RPi 4 in order to use low latency music performance software (specifically an app called Sonobus, as set up on this image, jambox-pi-gen: <https://github.com/kdoren/jambox-pi-gen>). Jack is used in Sonobus for audio. I'm having trouble getting enough input/output (with a dynamic mic, connected directly to the mini-jack input), so I experimented with the PGA Gain Left/Right  settings and raising those to the max (40db) enabled me to get good input levels. But I have a few questions/problems:

1. If I use amixer to set the PGA Gain levels instead of alsamixer, I get distortion (high pitched noise) as soon as they go above 0dB. Any idea why this is?

2. After making those PGA Gain changes in alsamixer, I can't seem to save them as I'd expect with the command

sudo alsactl store

That command returns this:

ALSA lib conf.c:1887: (_snd_config_load_with_include) toplevel:349:30:Unexpected char

Any idea how I can save these settings so I don't have to reset them each time?

Alternately, if there is a better way (than PGA Gain levels) I should use to increase the input/output settings please let me know. With the mics/headphones we're using, it just wasn't even close, because we're trying to avoid going through a headphone amplifier and coming straight from a dynamic mic. This is for mulitple kits for students and we're trying to minimize gear so I'm hoping I can solve this with the device hardware or software settings rather than add more audio equipment in the input or output paths.




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