PHP not processing second condition in OR

I searched alot and could not find a solution besides writing bigger code. What i request is only to be outputted if one of the two $btn_ strings is set.

In current state if $btn_orange = get_field('btn_orange') equeals true, ( $btn_black = get_field('btn_black') is not being processed while get_field('btn_black') returns a good value.

In short: $btn_black is not set if $btn_orange is.

This is my current code:

<?php if( ( $btn_orange = get_field('btn_orange') ) || ( $btn_black = get_field('btn_black') ) ): ?>

       <div class="buttons">

        <?php if($btn_orange && ( $btn_orange_url = get_field('btn_orange_url') ) ): ?>

            <a class="btn btn-lg btn-primary" href="<?php echo $btn_orange_url; ?>"><?php echo $btn_orange; ?></a>

        <?php elseif($btn_orange): ?>

            <span class="btn btn-lg btn-primary"><?php echo $btn_orange; ?></span>

        <?php endif;?>

        <?php if($btn_black && ( $btn_black_url = get_field('btn_black_url') ) ): ?>

            <a class="btn btn-lg btn-black" href="<?php echo $btn_black_url; ?>"><?php echo $btn_black; ?></a>

        <?php elseif($btn_black): ?>

            <span class="btn btn-lg btn-black"><?php echo $btn_black; ?></span>

        <?php endif;?>

    </div>

<?php endif; ?>

Now i could seperate btn_orange and $btn_black in seperate if blocks. But i only need <div class="buttons"> to be out putted if one of the two or both are set with the values of get_field().

can i accomplish this within the first if statement?