Advises about rom Samsung Galaxy A21S/A217F/DSN

Hello,

i need to find a clean rom for my Samsung Galaxy A21S/A217F/DSN.
My installed rom from french ISP is full of malwares ...Image may be NSFW.
Clik here to view.

does it exist open-source rom ?

Do you know a Samsung Galaxy A21S/A217F/DSN. rom without malware ?


Do you know a linux soft or microsoft windows app easy to install new rom ?

Thanks !