let
    Source = " Это текст с  несколькими   лишними      пробелами  между словами     ",
    words = Text.Split(Source, " "),
    realWords = List.Select(words, each _ <> ""),
    result = Text.Combine(realWords, " ")
in
    result

Text.Combine(List.Select(Text.Split(this, " "), each _ <> ""), " "),

fullTrim = Table.TransformColumns(#"Переименованные столбцы", {"Преобразование", asExcelTrim, type text}).

asExcelTrim = (this as text) as text => Text.Combine(List.Select(Text.SplitAny(this, "  "), each _ <> ""), " "),

let
    Source = "12-ЯНВ-21 100107449       Маска марлевая Move order      1023908        МТСрц            250,00  шт        6,00432        1 501,08",
    stringSet = Table.FromColumns({Text.Split(Source, " ")}),
    accRecord = List.Accumulate(stringSet[Column1], [string="", count=0], (acc, next) =>
        if next = "" then
            [string=acc[string], count = acc[count] + 1]
        else
            [string=acc[string] & (if acc[count] = 0 then " " else ";") & next, count=0]
    ),
    shrink = Table.Group(stringSet, {"Column1"}, {
        "temp",
        each if _{0}[Column1] = "" then ";" else _{0}[Column1]
    }, GroupKind.Local),
    toString = Text.Combine(shrink[temp], " "),
    result = Text.Replace(toString, " ; ", ";"),
    accResult = Text.TrimStart(accRecord[string])
in
    accResult

( this ) as text => Text.Combine ( List.Select ( Text.Split ( Text.Clean ( this ?? "" ), " " ), each _ <> "" ), " " )

( this ) as text => Text.Combine ( List.Select ( Text.Split ( Text.Clean ( if this = null then "" else this ), " " ), each _ <> "" ), " " )

= ( this ) as text => Text.Combine ( List.Select ( Text.Split ( Text.Clean ( List.Max ( { this, "" } ) ), " " ), each _ <> "" ), " " )