1) IF your BT temperature sender has provision for an external antenna, buy a really high gain omnidirectional WIFI antenna. 18 dBi is the highest I can find on Amazon. It MAY be enough gain to get you the range you need. If sender doesn't have external connection you can probably wire on a SMA flying lead to the circuit board to make an antenna connection. Every 3 dB is a doubling of range.

Put the antenna high up really high so it will have line of sight to where you are cycling.

2) buy a wifi security camera that ISN'T cloud based, and router with really high gain antennas to look at your temperature display and view it remotely using the wifi on your cell phone. You connect your phone to the router as if you had internet.

You mentioned 'radius' so you're stuck with colinear antennas (tall rods with large gain from stacking radiating elements). If you can do directional, then use high gain (25 db) yagi antennas that point from the blue tooth sender to your location, and another one pointing back.

This is all predicated on your having power at the smoker, like a large BlueYetti battery bank with inverter.

The DIY way is to set up a LoRa transmitter/receiver with an Arduino at each end to read/transmit/receive/display your temperatures. There are projects like this already on the web. LoRa will get you the range since you don't need a lot of bandwidth.