Question: how to convert a below set to expression?

let
expression := {{a*x}, {{(b*y)}/3}, {a*b}, {log(x+y)}, {3*x}};

I would like to convert the above expression as
 

requiredForm :={a*x, (b*y)/3, a*b, log(x+y), 3*x};

I observed that the function convert can do some convertion but have to use second argument + or *. which causes unstable results.

One method I found is to convert the expression to string and remove "{}" using StringTools:-Remove function.
I would like to know if its possible to do with out converting to String.

result:= convert(expression, `+`);

                                    /1      \              
   result:= {a b} + {a x} + {3 x} + { - {b y} } + {ln(x + y)}
                                    \3      /              

is there anyway I can get the requiredForm