There's probably a better way to do this, but I've just started using BLE Radar (F-Droid, Play Store), which can be set up to (among other things) tell you where your phone last saw a particular bluetooth address.
You don't get the benefit of the tracking network that iPhones, and now Androids, are a part of, and it's not built into the base system, but it's FOSS, and your location data stays local.
GUYS GUYS!! If we call their characters gay, we get sick bonus art!!!
GAY GAY HOMOSEXUAL GAY OMG SO GAY SO BEAUTIFULLY WONDERFULLY GAYYYYYYYYYY