Array formula to join header values in a Google Sheet when row values equal "yes"

I saw this question but was not able to get it to work for me. Since it is already answered and from an year ago I felt it best to post a new question.

I have a sample sheet at: https://docs.google.com/spreadsheets/d/1EqNfTWcNFgkv2gdovnH7JpqU9V2HG5Vkoup8bhNqI7k/edit#gid=0

In F1 I want an array formula that will join the values of B1:E1 if B2:E = "yes".

Column G has the expected output.

This is what I came up with but it's giving error:

={
    "output";
    ARRAYFORMULA(
        IF(
            A2:A = "",
            ,
            IF(
                B2:E = "yes",
                TEXTJOIN(", ", TRUE, B1:E1),
            )
        )
    )
}