Recommendation for Inexpensive Sensors to work with SmartThings?

Tuya Zigbee devices tend to be among the most complex to pair with SmartThings, because they use a lot of proprietary code.

See the community FAQ for a step-by-step description of the process to get them to work:

FAQ: Using Tuya Zigbee Devices Directly With a SmartThings/Aeotec Hub (2024)