Is that figure a monthly value or a "total customer value", e. g. One-time indulgence payment?

And would 26€ per month also remove all Google ads from the Internet?

26 in what period? Like over the life time, year, month?

The ad business requires Google to hire a hell of a lot of developers who are not working on the search engine. A pay service would be viable on less revenue. And nobody knows who many people are actually willing to pay for Google search because we've never had to.