Fill down first cell after Null/blank

Step 1. Add Index column

Step 2. Add marker column to find Room names

Step 3. Add new column: Room

Step 4. Fill it down

Step 5. Leave only few columns with filter on marker = false and ColumnValue <> ""

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bZDNCoNADITfZc/bQ3+eQNsiFUUU9CAeggYtTTfFn8L69LVxaS9elpmE+TJsWaqU+bnbq0qXqoC+0TeROUxtB0aH4nwCO7LRsbgzG34vu0Kc13P9cKn/I9SDyISJvmBfXMz0w3pApFORAfMLex25sNXXLeBxRbSTReOCIeHd6IvoCIalZCY6A1N3ODtODoRmnpDArbfop7UU9u3SxFvniAO6SxkQDO5SAiOS+44AbLPUyVVVfQA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ColumnValue = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"ColumnValue", type text}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
    #"Added Marker" = Table.AddColumn(#"Added Index", "Marker", each let
currentIndex = [Index], currentValue = [ColumnValue],
previousValue = List.First(Table.SelectRows(#"Added Index", each [Index] = currentIndex - 1)[ColumnValue]),
marker = if (previousValue = "" or previousValue = null) and currentValue <> previousValue then true else false
in marker),
    #"Added Room" = Table.AddColumn(#"Added Marker", "Room", each if [Marker] then [ColumnValue] else null),
    #"Filled Down Room" = Table.FillDown(#"Added Room",{"Room"}),
    Result = Table.SelectColumns(Table.SelectRows(#"Filled Down Room",each [Marker] = false and [ColumnValue] <> ""),{"Room","ColumnValue"})
in
    Result