IMHO, when you enable Scheduled events to run in local, you must be able to test this easily if it is not running in a long interval. Never faced issues with start date time, because the time you set is only start date time and if it is in past, your scheduled events will be running immediately after your start your application and if it is repeating.
Now to your other question:
Hope this helps.
You need to enable the Scheduled event and ensure the timing is set in such way that its worth waiting.
Though if you want to test if the ScheduledEvent will run; It will, only timing UTC/Server time etc. needs to be configured correctly. Testing the timing; I would not rely on your local machine. Since server config != local config.
If you want to test the microflow behind the SCheduled event; I use this trick
Reason I use a test microflow is to avoid security incidents. By using ACT_TEST_[WhateverIwantToDo] you can search for “ACT_TEST” before deployment to accept/prod servers and ensure that security for scheduled event microflows is correct at all times.