I don't necessarily think this game needs progression at all. Wordle is a game where you gain information with each attempt. Triword doesn't need any additional information at all. There's one solution (or should only be one solution), and it can be deduced from only the information provided.

If there is any kind of progression, I could imagine it just being successive hints:

- One random letter, but no information about placement - The correct placement of the random letter in the affix - The correct placement of the affix to the stems

But really, I think the simplicity of this as a pure logic puzzle is great all on its own.