they're a big company but they can't able to filter those phishing and malicious links that who paid ads
Actually, google also has a mistake here in accepting fake websites they should manually review websites before they release it to the public as ads.
Google don't care. You think a multi-billion dollar company like Google can't hire a couple of people on minimum wage to check the authenticity of ads which are submitted? Of course they could, they just don't care. Google are not your friend. They don't care about you, your data, your coins, your privacy, your security, your computer, your phone, your life, anything. They care about money. If a scammer is willing to pay money to advertise their scam, Google are quite happy to accept. If a scammer is willing to pay money to have their malware infected app listed on the Play Store, Google are quite happy to accept. As long as they make a profit, they don't care in the slightest if people lose their life savings to a scam ad they are showing.
This has been going on for
years. Google have proven time and time again they are quite happy for users to have their lives ruined as long as they keep making those sweet, sweet profits. Still using Google products or trusting Google with anything is pretty much Stockholm Syndrome as this point.