Did Google change something in approx September 2024?

I have a small site (psychotherapy). It has no backlinks pointing to it and is ten years old but it has good content. It's always done very well (by my needs), which I have assumed was due to high engagement. Up to around last September 2024 it was producing many leads. In the September - December 2024 it dropped sharply down the ratings, and visitors dropped by two thirds. There are tons of things to investigate, but a starting question is whether google changed anything around that time - took a dislike to something, got stricter about something, started to prefer sites with certain attributes, etc? With many thanks.