It seems your site is using plugin cache site, This makes the desktop interface saved and reused when accessing via mobile
please enable mode cache for mobile, about this, please contact the author of plugin cache site to enable this mode.
Now, please disable the plugin Cache site to check your site.
And please delete cookie your browser before checking your site.
Example, on our theme are using WP Rocket plugin: https://prnt.sc/pld4jn
Thanks for watching