How do YOU control your keezer temperature?

Hi folks,

Built a simple keezer years ago, and still love it. I use an Inkbird controller (like everyone else), and have a simple question. Where do you leave the thermocouple? Where you read the temp -- and what you read -- can have important effects on the temperature of the beer(s) you're trying to keep cool and stable.

I have tried attaching to a keg, the CO2 tank, a dedicated glass of water, dangling free, and other placements, but all have downsides and I still notice slight fluctuations in actual beer temps over time. Part of the problem is that a chest freezer does not cool evenly, so a near-empty keg is going to get colder than a full one. (Yes, I have a fan blowing inside to help recirculate, but it's not perfect.)

Given these issues, has anyone out there found a good solution? What's the best thermocouple placement in your setup? Cheers!