Is it possible to achieve approximate location of the tags using LoRaWAN or Bluetooth, without relying on GPS?

With Bluetooth: Yes.

With LoRaWAN: Yes. It supports presence detection, with an accuracy of a few hundred meters. Alternatively, you can deploy four LoRaWAN gateways spaced about 1 km apart (as an example). In this setup, the accuracy can range from tens of meters to a couple of hundred meters.

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