I find repgrep defaults sensible when searching for text but fd misses files that I expect it to find -- this has happened a few times now and I have gone back to find.
For instance: 'fd .apk' to search for android builds.
Unlike find, fd follows the rg approach of respecting VCS ignores, which does have both advantages and disadvantages. But if you know you’re specifically searching for a binary, just pass -u (once to include VCS-ignored files, or even twice to also include hidden ones) and you’re golden. In your specific example you probably also want -F (fixed string) or -g (glob), because fd does regexes by default and I doubt you want to type '\.apk'.
As to find, its flexibility certainly comes handy on occasion, but...
Have you looked at the original man pages for 7th ed. (http://man.cat-v.org/unix_7th) or Plan 9 (http://man.cat-v.org/plan_9_3rd_ed)? They’re basically tldr with less examples, and exhaustive, except there’s so much less stuff to exhaust. I was both pleasantly surprised by how simple they are and unpleasantly surprised by how far we’ve fallen in terms of complexity (though my recent comment https://news.ycombinator.com/item?id=27498189 explains why that’s an oversimplification). The GNU man pages (where they even exist) or the POSIX ones are a usability abomination in comparison. Even BSD’s are still quite bad.
[0]: https://github.com/sharkdp/fd
[1]: https://tldr.sh/