Plain answer
Separate accountability from accompaniment. You do not need another person beside you; you need a clear commitment, a deadline, and a result that matters outside your private log.
Choose what will notice
A coach, partner, public log, paid commitment, event, or virtual team can all create consequence. Pick the lightest structure that changes behavior.
Avoid coordination debt
If every run requires messages and calendar agreement, the accountability system adds another failure point. Asynchronous structure is often better for irregular lives.
Use a weekly horizon
Daily streaks punish necessary rest. A weekly result creates urgency while leaving room to move the run.