How to get excerpt correctly formatted

I'm using a theme that use the_excerpt() function to show the excerpt of the post.

All posts have not set custom excerpt, so the_excerpt() returns a piece of post content.

In some post first paragraph contains a br, for example:

pMy new question is:brwhy words are not separated by a white space?/p

The text rendered is:

My new question is:why words are not separated by a white space?

Following this post I implemented this solution:

function my_excerpt($text = '', $raw_excerpt = '') {
    add_filter('the_content', 'my_content', 6);

    // get through origin filter
    $text = wp_trim_excerpt($text);

    remove_filter('the_content', 'my_content', 6);
    return $text;
}
remove_filter( 'get_the_excerpt', 'wp_trim_excerpt');
add_filter( 'get_the_excerpt', 'my_excerpt');

function my_content($text)
{
    return str_replace( 'br', ' ', $text );
}

And this works, but I have two questions:

1. Why the_excerpt() doesn't substitute br with space?
2. Is there a better way to achieve this result?

Also, I'm quite new to wordpress development, any suggestions to improve my code are welcome.

Update: I found that is reported this issue, but unfortunately is still open.