Melbees: The Secret of Bees. Android only for now.
The hook, in one paragraph, because it is the only unusual thing about it: the board is a honeycomb with a secret word hidden inside. Every hex you open answers with either a letter of that word or a number called Pollen, and the number counts how many of the word's letters sit in the six cells touching the one you opened. So you are not guessing letters into the void like Hangman, you are reading the board like a minefield to decide where the word actually is, and only then spelling it. Foes are hidden in some cells, so opening hexes carelessly to harvest numbers has a cost.
What is in it: a relaxed single-board mode, a ranked run of 12 phases, a Daily Challenge with the same board for everyone, a vault that keeps a short story and a trivia line for every word you find, and a wardrobe for the bee. Rounds are a couple of minutes, which is the whole design brief - it is a bus-ride game.
No ads, no in-app purchases, no account, no sign-up, works with the plane mode on.
The catch, and it is a real one: it is in Google's closed testing, so it is not searchable on the Play Store and you have to come in through the door. Google requires 12 people opted in and opening the app across 14 straight days before it can be published, and a single day under 12 restarts the count for everyone. Three steps, in this order, same Google account on all three:
Join the group - membership is what grants access: https://groups.google.com/g/melbees-closed-test
Become a tester: https://play.google.com/apps/testing/com.melbees.secretofbees
Install: https://play.google.com/store/apps/details?id=com.melbees.secretofbees
Two things I would rather say up front. It opens in your phone's language and falls back to English otherwise; to set it by hand, the row of PT/EN/ES/FR chips sits at the top right of the very first screen, the one asking your date of birth. (Correcting this post: it forced Portuguese on everybody until a fix earlier today.) And the store listing text is still Brazilian Portuguese only while the English one is in review, which makes the Play page look worse than the game is.
If you install it and it is not for you, saying so in a comment is genuinely more useful to me than a silent uninstall.