[logbiscuitswave]

An nRF52 dev kit is like $30. It’s probably not worth the time and aggravation to try to repurpose one of these COVID tests unless you’re really determined. Nordic is one of the better vendors - their tools and docs aren’t too bad.

[floatboth]

You also do not have to use their tools. Use Rust with nrf-rs, or Apache Mynewt (with a fully open source BLE stack), or libopencm3, or…