Tbh I am a messy person, I trained myself to be organized but I still struggle to not lose my keys and I want something like the apple tag but FOSS, I’ve thought of an ESP32 or ATTINY with a bluetooth module but I don’t think apple uses that? It has to be durable and friendly with LineageOS, samsung stock and my dad lol.
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.