Like I said Before,
1. I think, you have customized the site and it messed up the responsive. Please Download and install the fresh theme, in the test server/blog and compare the things.
2. Your site images not compressed and total image size is more than 2.4MB
3. You have few unnecessary plugins that slows down your site (How? Because, You can check our demo site with Google developer, and tell us the score)
4. One of your plugin the query strings in image files.
5. You have no CDN, Cache and like that. Many More details, you can get in the Page Speed insights.
6. If you are in shared hosting, you can’t expect speed.
Here, I’ve shared some of the issues in your site. Fix all the above issues then check your site with page speed.
Thanks. Hope you got it.
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