Your sample form makes things unnecessarily complicated by returning it's value as msg.payload["Date "]. Once I got rid of that space it was much easier.
The ui-form returns the selected date as 00:00:00.0000 on that date, formatted as an ISO datetime string (Timezone Z or Zero or Zulu)
So at 23:08 GMT +1 on 7th June it returns {"Date ":"2024-06-06T23:00:00.000Z"}
ie it converts my time (BST) to UTC and returns it as a string.
To get it back into GMT I need to convert it to a date object, eg with a function node.
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