Sorry for the delay, you know how life can be
I was able to get some probes on my three current sensor (L31S200S05FS) outputs and take some basic captures while attempting to throttle up.
These are taken right at the J8, J11, and J14 terminals, which explains the dirty signal. I also quickly checked the spectral contents of one of these signals, and it looks like the (relatively) high frequency is primarily at ~10kHz. I'm not sure where this is coming from, as the ATTiny should be either 62.5kHz or 100kHz; I'll have to do another FFT, this time up to around 200kHz. I'll also verify (again) the output of the ATTiny to make sure it's not acting funky.
I'll follow up with some pics of my setup as well in case there's anything obvious that I'm missing. Here's a link to a short clip I took of myself attempting tho throttle up a few times:
https://streamable.com/a6heg
I've got too much invested in this not to see it though to the end