Custom devices require custom solutions.
I suggest using Python (don't be scared).
This tutorial shows us how to read data from serial and save it to .csv file. You don't have to use a file. For example you can modify it to use an in memory list, and save just values from last 30 seconds. You can also read several values, and not just one.
ser = serial.Serial('/dev/ttyACM0')
ser_bytes = ser.readline()
decoded_bytes = float(ser_bytes[0:len(ser_bytes)-2].decode("utf-8"))
with open("test_data.csv","a") as f:
writer = csv.writer(f,delimiter=",")
This tutorial (and this one) shows you how very quickly to show a sophisticated plot of the data you collected. You can even make a plot that shows several graphs and updates in real time.
import matplotlib.pyplot as plt
Don't be scared it's not black magic. It just takes few days to understand how things work.