How to increase opencart3 website loading speed?

Question

opencart

Patient: aydadom-spb.ru
How to increase download speed? In google page speed I get an error for the pc version.
All js and css compressed...
Images compressed...
What could be the problem?

Answer 1

Main page:
1. The server collects the page in 7s - this is a very long time (at least 0.5-1s)
2. 316 requests, 13.7MB - use lazy loading
3. html at 13.7k! lines - rendering, especially mobile, obviously will not say thank you