Are billboards or radio stations or television channels unethical to you? Because they are also trying to "manipulate" you into buying things.
Advertising is not inherently unethical. I want people to buy my product so I need to raise awareness of it, encourage people that it is the best, make them feel like they need it.
I would even go so far as to say that Google's default anonymized model makes this far better. My preferences can be used to serve more meaningful ads to me which makes everyone happier. Eg, I was searching for tent reviews online. Saw an ad for a tent from a brand I had never heard of. Looked up their reviews and bought that tent.
Unfortunately, they are a lot of bad actors in this space. Google is actively trying to weed them out. They are deeply incentivized to rid the internet of them because it means less ad blockers and less spam and more money for them.
Any website you visit or app you use is going to collect some personal information about you. How many times have you questioned why you need to turn over your email to a stopwatch app. At least with Google's default-anonymized model, you are opting in to a fairly sweet deal. You volunteer things you are interested in so that Google can serve you better ads and keep the internet free (in the dollar sense) and the information you provide is not reversible back to you.
Doesn't sound too unethical to me especially because it is all one big opt-in.