change zPosition of tiles

I want to change the zPosition of some tiles in my tile map. I use the following function to achieve this:

 static func setZPosition(to tileMap: SKTileMapNode, and tileInfo: String){

    let tileSize = tileMap.tileSize
    let halfWidth = CGFloat(tileMap.numberOfColumns) / 2 * tileSize.width
    let halfHeight = CGFloat(tileMap.numberOfRows) / 2 * tileSize.height

    for column in 0..<tileMap.numberOfColumns{
        for row in 0..<tileMap.numberOfRows{
            let tileDefinition = tileMap.tileDefinition(atColumn: column, row: row)
            let isCorrectTile = tileDefinition?.userData?[tileInfo] as? Bool
            if isCorrectTile ?? false{
                let x = CGFloat(column) * tileSize.width - halfWidth
                let y = CGFloat(row) * tileSize.height - halfHeight
                let rect = CGRect(x: 0, y: 0, width: tileSize.width, height: tileSize.height)
                let tileNode = SKShapeNode(rect: rect)
                tileNode.position = CGPoint(x: x, y: y)
                tileNode.zPosition = 100
                tileMap.addChild(tileNode)
                print(tileNode.zPosition)
            }
        }
    }
}

When I use this function, the print statetement shows me 5 times "100". This is correct because I want to change the zPosition of 5 tiles with the userData name "Z", which I use as the tileInfo parameter. The player sprite has a ZPosition of 10. But if I walk now with the player over a tile with zPosition 100, the player is still above the Tile. I want him to be behind the tile. What I'm doing wrong here?

There is nothing in the definition that allows for zPosition change (Which would make sense since the idea is to draw the tiles as fast as possible)

I would recommend having another tile set overlay it, or have individual sprites that pop out.