How to beat "Mobile-friendly" and "Resources failed to load" on google?

Question

Google

The number of pages with errors on the site is constantly increasing The font is too small and Interactive elements are too close
When opening the page, the corresponding inscription hangs: The page is not optimized for mobile devices
I click "check on the site" and then 2 options: either the page is optimized, which does not affect that it remains in errors, or the page is not optimized, and in the results of the check the following:
Page
resources 17 out of 19 resources could not be loaded, including CSS with the value: Another error
In other words, it does not stupidly eat CSS, but makes a clear conclusion that I have errors ...
How can this be fixed?
The only thing that comes to mind is catching it by agent, and inserting CSS into HTML (and maybe JS too)

Answer 1

you - did not hide, and in Joomla by default they are closed.
in robots.txt at the root of the site add
User-agent: Googlebot
Allow: /*.js
Allow: /*.css

Answer 2

Set to the page "Check optimization for mobile" run the test.
If errors appear, click on the link "Page loading progress data"
You will see something like this and you will immediately understand everything.
Retrieved May 14, 2021 at 11:16 am
Page partially loaded
Failed to load all elements of the page. This may affect how Google sees and processes your page. Fix problems.
Details

User Agent
Googlebot for smartphones

Failed to load 20 page
resources Resource Type Status
 https://an.yandex.com/system/context.js Script Googlebot access blocked in robots.txt
 https://family-link.ru/wp-content/plugins/litespee... Script Googlebot access blocked in robots.txt
 https://family-link.ru/wp-content/plugins/litespee.. Script Googlebot access blocked in robots.txt file
 https : //family-link.ru/wp-content/plugins/wpdiscuz... Stylesheet Googlebot access blocked in robots.txt file
 https://family-link .ru/wp-content/plugins/wpdiscuz... Script Googlebot access blocked in robots.txt file
 https://family-link.ru/wp-content/plugins/wpdiscuz... Stylesheet Googlebot access blocked in robots.txt
 https://family-link.ru/wp-content/plugins/wpdiscuz... Stylesheet Googlebot access blocked in robots.txt
 https://family-link.ru/wp-content/themes/familylin.. Stylesheet Googlebot access blocked in robots.txt file
 https : //family-link.ru/wp-content/themes/familylin... Script Googlebot access blocked in robots.txt file
 https://family-link .ru/wp-content/themes/familylin... Stylesheet Googlebot access blocked in robots.txt
Lines per page:
1-10 of 20
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JavaScript console
messages Message Source Time

Access to XMLHttpRequest at 'https://mc.yandex.ru/watch/56486578?wmode=7&page-u... ' from origin ' https://family-link.ru ' has been blocked by CORS policy: No 'Access-Control-Allow -Origin' header is present on the requested resource.
https://family-link.ru/family-link-analogi/:0 00:02.000