Lost 90 positions in SERP

Hey guys,

I explain fast : I've got a website about drones reviews : Drone-store.fr
I was first page in SERP during 2 years, with the word "Drone" in Google France

Then about the 13th January, i lost several places(10 positions). Then the 7th Febuary, I lost again (50 positions) until no longer be part of research around 20 March.

Do you have a clue what is for ? maybe something wrong in my website ? or google ?
I show you the graphics...

Lost 90 positions in SERP

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