What do You suggest for Google Ads as A Safe Site?
Wordpress website as a dummy or HTML?
Let me know which one is the best.
Thanks
Basically, the more it looks like a real website, the better. Wordpress is certainly a very good choice as millions of people use it to run their websites/blogs.
Most people claim that HTML sites are better for cloaking Google Ads but I don't really agree with that. Wordpress powers more than 30% of all websites on the internet and is certainly not a footprint.
Some of our clients are running with WP sites without any issues, while others prefer to stick to the tried & tested HTML sites, so it's pretty much a personal preference.
Just make sure to have all the required legal pages such as TOS & Privacy Policy, and its also a good idea to have a Contact Us page the details of which correspond to your account's info 
It does not matter. What matters is your safe site is believable as a "real" site. What also matters is how you are setting up accounts and your cloaking methods.