Phew, glad to see others found this difficult. The central device perhaps similar to Paul’s recent “CO” puzzle. 18 and 20d provided a way in. I did wonder if the use of different letters has a significance other than the surface reading, but I guess not.
Not sure about 14d unless I’ve misunderstood the ‘delicate and magical’ bit. And I’m still to parse 25a despite earlier comments.
Also not sure of the need for the ?s in 1a and 2d.
Liked 3d and 19d.
Does anyone have a green tick? If so, I’ve definitely gone wrong somewhere!