First of all, to be clear, I am not complaining that less and less visitors are visiting my website. My problem is very different.
In my GA4 explorer, I checked last week how many users had accessed my page between the 1st of November and the 9th of January and I obtained a total number of users of 6930 users for a specific country.
Today, I checked how many users had accessed my page between the 1st of November and the 16th of January (i.e. same period + one more week) and I obtained a total number of users of 6348 for this same country.
Why is my total number of users decreasing over time? I gave the example of a specific country, but it happens for every country in my report.
I have checked if it could come from sampling but it is written in my report that there is no sampling (the report is based on 100% of the data).