Regex replace with a small text change?

I need to convert some HTML content to UBB code, for instance replacing the < > signs by square brackets [ ].
There also may be an ordered list <ol> tag with a start= attribute specifying the kind of marker.

const str = '<b>Something</b> is going on.<br><i>But what?</i><br><br><ol start="3"><li>First</li><li>Second</li><li>Third</li></ol>';
const regex = /<(/?([bisu]|li|ul|ol|ol start="d+"))>/gi;
let result = str.replace(regex, "[$1]");
console.log(result);

This works as expected, but I’d like to remove the quotation marks, so the <ol start="3"> will become [ol start=3]. I wonder if this is possible in the same regex.