First I’d like to recommend (temporary) replacing the power supply and the cable with a 5V / 2A or up Samsung or iPhone one.
Then start Homey in Recovery and select “Full software download”
Nothing should get lost.
Several users confirmed this as solution.
And to answer the other part of your question
When you “Reset” zigbee, all zigbee devices have to be paired as new devices.
And all related flows have to be fixed.
But a neat script exists for fixing the flows.
But I don’t think resetting it solves your ‘zigbee is not started’ issue.
