Simple Metronome is open-source. Its at early stages, but will improve over time.
Features:
* Free & Open-source
* Dark mode
* History tracking
* Accurate & efficient
* Multiple time-signatures
On top of remembering settings after being closed, after each session (start/stop cycle) the app will store the date, duration and tempo for later review.
Source code is on the "Augmented Audio" GitHub repository.