Yeah it's always been pretty clear to me that the intermediate plans exist mainly to annoy people into buying the most expensive ones.

You know, in for a penny...

There's also chesstempo for puzzles if you are not aware of it already, the puzzles are great and free, with subscription tiers for more features (unlimited endgame puzzles, custom puzzle sets, opening trainer etc.). The UI is ugly, clunky and old, but as long as it is only for puzzles and not playing I can stand it

I’m getting increasingly frustrated by the puzzle quality. Puzzle difficulty is determined algorithmically using an Elo system (where essentially puzzles play against players). That sounds great in theory. The problem is that there’s no penalty for guessing, in fact, the UI forces you to make a guess. This means the rating partly measures guessability instead of solvability. At my low-ish rating, I get a mixture of puzzles I can realistically solve, and extremely hard puzzles where the obvious dumb guess happens to also be the correct solution. I’m not sure if anybody else is annoyed by that as much as I am.

The biggest benefit, in my opinion, of doing puzzles is building pattern recognition. If that obvious dumb guess is consistent for the structure presented in the difficult-but-guessable puzzle, then I think there's still value to doing it.

It's not; that's the point.

Level 1000 puzzle: obvious pattern move is correct, no surprise.

Level 1400: obvious pattern move is correct, but you have to check a potential threat unless you are guessing.

Level 1800: obvious pattern move is incorrect, need to notice the threat and findnthr better move.