Using a template file for a specific custom URL

I don’t know what nepal is (text prefix only or maybe taxonomy term), but it is not the most important thing, you will correct it if necessary. Rewrite rule like this should resolve the case.

add_action( 'init', 'se356109_events_custom_rule' );
function se356109_events_custom_rule()
{
    add_rewrite_rule(
        'nepal/events/(.+?)/([0-9\-]+)(:?/page/?([0-9]+))?/?$',
        'index.php?events=$matches[1]&paged=$matches[3]',
        'top'
    );
}

If you need to use URL date (in your example “2020-01-10“) somewhere, you need to add a new query variable (with any name, e.g. custom_dt) and modify rewrite rule.

add_action( 'init',       'se356109_events_custom_rule' );
add_filter( 'query_vars', 'se356109_query_vars' );

function se356109_query_vars( $vars )
{
    $vars[] = 'custom_dt';
    return $vars;
}

function se356109_events_custom_rule()
{
    add_rewrite_rule(
        'nepal/events/(.+?)/([0-9\-]+)(:?/page/?([0-9]+))?/?$',
        'index.php?events=$matches[1]&paged=$matches[3]&custom_dt=$matches[2]',
        'top'
    );
}

And that’s how you read the value of this new variable:

$dt = get_query_var('custom_dt', false);