Why did the site load speed drop?

Question

Performance evaluation

Hello! Transferred the site from the test server to the working one. At first, all indicators were good (about 100 in Google Speed), but just a week ago they began to sag to 70-30. At the same time, there were no global updates, except for the addition of Yandex.metrics. TTFB has increased, but the selections from the database are generally ridiculous - 5-6 entity instances (maximum 3 entities per page). Tell me, what could be the reason for this?