How to tell which monitor has a more true color?

Hi all,

I have two monitors, one is an LCD and the other is a Huion tablet monitor. On my tablet monitor is where I tend to color pick, because obviously I'm painting on that one, but once I finish and drag it to my other monitor, the colors look more dull and desaturated and sad. I just now tried to compare the same drawing on both monitors, and then to my phone, and my phone was super warmer than both. What's my best option? Does anyone have experiences with this?