Google Search Console poor URLs on mobile

I have problem, that Google Search Console says i have bad url on mobile. At the same time there are no problem on desktop… How a can fix that?

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

I would start by opening the report to determine what the problem is. Your question is way too general for a specific answer.

Looks like Google says pages are slow to load.

For example : ActiveCampaign SMS: Two-Way Text Messaging Integration

But on this page has nothing to be slowly. No animations, all pictures compressed…

Dive into the details. Look at every script you add to the page load and look it the impact. Add This will never be found on a site I build for example. Performance tuning is a process and takes knowledge and experience. There is no click-a-button fix. I have been doing it for 20+ years. Consider hiring talent if this is beyond your skills.