Certs not running & website became a mess

no. it does not work.
Whenever I change the HTTP to HTTPS on /wp-admin/options-general.php. The website looks messed up.

Now what I need to do is to just adjust my theme first right ? change the http to https in the theme. because it was coded with http.

I also can't access WP-Admin when it is directed to HTTPS

It isn't. You have to explicitly set the HTTPS variable in Apache - there's no implicit parsing of x-forwarded-proto.

So WordPress thinks it's never in HTTPS mode and loops pointlessly.

SetEnvIf is valid to put in a lot of places. For example, you can put it directly inside your <VirtualHost>.

Point taken. Or we can lie to wordpress: WP behind reverse proxy all content insecure | WordPress.org

THANK YOU so much. it worked.

But some contents are not showing. Need some little adjusment.

:pray: :pray:

Super! As I mentioned before, https://www.whynopadlock.com can be a valuable tool to identify the resources which are not being loaded.

Thank you @9peppe for the help too. forgive me for being so stupid. :pray:

Don’t worry about it, we all can be impatient from time to time.