HTTP/2. Why is the site loading slowly over https?

Question

Digital certificates

Hello! Site on Wirth. hosting from Beget. We decided to switch to the HTTP / 2 protocol, because. multiplexing, speed and all. The Let's Encrypt certificate is issued and connected by Beget, without our participation, just click the "Install Certificate" button in the PU.

After switching to a new protocol over a secure connection, the site began to load for a very long time on the first load, 3 times slower than it was before. In .htaccess, I removed the redirect so that you can see the difference. Tested on different devices, with different Internet connection speeds and with different providers. Everywhere the same story.
I tormented support about this, but apart from bringing screenshots and "everything is loaded equally well with us" I did not hear.

Links to the site: stroi-ka.org andhttps://stroi-ka.org respectively.
Hope you can help figure it out. Thank you!

Answer 1

H1.1:
H2:
First you need to open the Network panel in the browser and find out what exactly caused "it took a very long time to load" - the server takes a long time to respond, the connection takes a long time to establish, scripts block rendering, or something else.

Answer 2

I noticed that different requests are made from Yandex (apparently some kind of "tracking" script for user actions for statistics). Try turning it off first.
PS: my site loaded in 2 seconds.

Answer 3

Same problem. one server, Let's Encrypt certificates are received everywhere, but on one domain sll is loaded for 10-15 seconds, and after a time, I can't understand what the problem is.