I have a domain that was ranked #1 for a decade, it always had GA. I removed GA replaced it by Piwik, it dropped in rank. Nowadays I'm not eben on the 1st page

I have a domain that was ranked #1 for a decade, it always had GA. I removed GA replaced it by Piwik, it dropped in rank. Nowadays I'm not eben on the 1st page anymore, despite having the most authentic design and simple use.