Slider Slicer that Includes Time (Not just Date)

No, that is not possible. Use the filter pane instead.

I was able to make a time slicer, but it was indepentent of the date, so you would first have to filter the date and then the time.

In power query, I split the time and minutes from the timedate into text, then converted back into a number (the minutes need to be padded with a zero):

Number.From(
Text.From(Time.Hour([Timestamp_Time])) &
Text.PadStart(Text.From(Time.Minute([Timestamp_Time])), 2, "0" ))

I created a slicer with the number in it (used Greater than or equal to, but Between also works):

To get it to look like time, I formatted the number to 0#:##