If you are going the phone way and care to make the battery last longer, you can also install an app that keeps waiting to receive a keyword by SMS, upon receiving which it turns the GPS on, locates itself and sends the location back by SMS. It has dual benefit of not needing a data pack and making the battery last longer since the GPS or data is not on constantly. On the down side it’ll be tough to do live tracking by this approach.

https://www.theonespy.com/features/track-location-with-sms

https://youtu.be/FknRti6n_F8

These are just two links that came up using a basic search to do this. There are multiple listings on f-droid to help you not just get location but control the phone remotely over SMS.

Find My Device (FMD) (Locate and control your device remotely) https://f-droid.org/packages/de.nulide.findmydevice/

Simple sms remote (Control your device by sending text messages) https://f-droid.org/packages/tranquvis.simplesmsremote/

Finder (Remote mobile phone searching via SMS requests.) https://f-droid.org/packages/ru.seva.finder/ Cheers!

Yeah, this is why our AI image generators create kooky images sometimes. /s?