What I might do is use the today() plus time to get it to be like midnight for the day, similar to John's solution above:
(.<=(today() + (1000 * 60 * 60 * 12)) which adds 12 hours to today()
Or what I do formatting my dateTime (though this might be extra for your use because this came in when I started using Power Automate and needed to pass the time through it and I was having timezone issues) is:
format-date(${ServiceDate},'%Y-%m-%d')+"T23:59:59 [Halifax]"
I use this to set a dateTime field in my survey to the ServiceDate (which is selectable by the user, but defaults to today() and I can't imagine why you can't just plug that in directly) at 11:59pm.
The [Halifax] is for the Atlantic Timezone, I prefer this instead of the -03:00 for daylight savings reasons (as far as I can tell it does it right this way). I'm guessing for Eastern time for Mass (great state) it'd be [New York]. Or you might be able to use the pulldata("@property",'utcOffset') in the calculation instead.