Interface Date Field input customization

Within the Appian interface, the date field typically accepts dates separated by a forward slash ("/"). However, in our use case, there are scenarios where we need to support dates separated by a hyphen ("-") or a pipe ("|"). To accommodate this requirement, I’ve written the following piece of code

a!localVariables(
  local!onlyNumbers: cleanwith("1.22.1957", "1234567890"),
  local!length: len(local!onlyNumbers),
  if(local!length = 8,
  concat(left(local!onlyNumbers, 2), "/", mid(local!onlyNumbers, 3, 2), "/", right(local!onlyNumbers, 4)),
  if(local!length = 7,
  concat("0", left(local!onlyNumbers, 1), "/", mid(local!onlyNumbers, 2, 2), "/", right(local!onlyNumbers, 4)),
  null
  )
  ))

It seems that the Appian interface is not executing the logic as expected, and the error still persists.