I'm not sure what point you're trying to make here. You start by agreeing that telegram is simply not private. Then you move on to implying that it must be, because the CEO got arrested?
How does that change the fact that it is, by your own assessment, not private?
To answer your question, the answer from my perspective is quite simple. Noncompliance. If telegram had complied to local laws, like the others have and continue to do, he would not have gotten in trouble.
Not an endorsement, because I've never used it, but kagi is an alternative which I believe has it's own index. It isn't free though
There is also searxng which is more of a meta search that will post your query to a bunch of search engines at once