It has been 4 days since I am waiting for your response.
he LCP score is indeed mainly affected by the loading of JavaScript files, as you have pointed out earlier in the ticket. On your website that JavaScript code comes primarily from the Google Tag Manager implementation. You have a plugin named gtm-kit with which you load various analytics JavaScript code and about 85% of the JavaScript loading time is related to code brought through the Google Tag Manager:
For the sake of testing purposes, I disabled temporarily the gtm-kit plugin and retested the mobile performance with the Google PageSpeed Insights too. As you can see from the results below, the mobile score was instantly increased to 73:
Especially the GTM ones. And those scripts are being triggered by these inline scripts, which are being excluded from Delay JavaScript execution by adding the attribute data-nowprocket:
I will try to explain myself as clearly as possible:
For WP Rocket to be able to delay the execution of a script, that script must be present in the HTML of the page, only then WP Rocket can add the RocketLazyloadscript attribute to delay it, but if that script is not present in the HTML but is dynamically triggered (as in this case) by a script that was itself excluded from the feature, then WP Rocket will not be able to delay it and therefore that script will end up affecting your score if it consumes too much execution time.
Those scripts (which in turn are instantiating GTM scripts) are being excluded from Delay JavaScript execution because the data-nowprocket attribute has been added to them:
