Can't access dashboard, disabled theme and plugins already

I see an error that’s not a WordPress problem:

mysqli_real_connect(): Headers and client library minor version mismatch.

There are lots of suggestions here:

https://www.google.com/search?q=mysqli_real_connect()%3A+Headers+and+client+library+minor+version+mismatch

You may want to qualify that search to add more info about your server environment

I looked through a couple of those links, is that something my hosting provider has to do?

Yes, contact tech support for your host.

Okay I contacted them, is this the problem with my site though? I was able to access my site fully last week, and then some theme issues arose, now it is completely gone.

Definitely seems that way. Quite possible the host messed up updating php/mysql.

Alright I disabled plugins in the wrong DB.. whoops. But some of the site is back now, and I think the reason why I’m having issues is I may be enqueueing scripts incorrectly. I only have

add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_styles' );
function my_theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );

}

in functions.php, do I need to add stuff in every css file?