Check your code. As far as I see you used getTimeParams().startDate as a value for startDate. Maybe the problem in that value. If you will use proper value for schedulerRef.startDate, you will get the result you need.
Try to use new Date() ?
A flag which indicates what time should be used for selected date. false by default which means time is reset to midnight.
Possible options are:
false to reset time to midnight
true to keep original time value
'17:00' a string which is parsed automatically
new Date(2020, 0, 1, 17) a date object to copy time from
'entered' to keep time value entered by user (in case format includes time info)
When you set it true, it will keep the original time value. You need to pass a date object to copy time from.
This is the code you need:
const dateField = schedulerRef.tbar.widgetMap.datePicker;
dateField.keepTime = new Date();
dateField.value = new Date();
dateField.keepTime = false; // to prevent applying current time when using datafield arrows
Original value for keepTime in the field config should be false as well. Just omit it, it false by default.
Please also check code of your onChange handler in you datefield. I am not sure if you need all that logic with diff in your solution, maybe you simply need