Is it possible to cancel spending branches after block height?

I want a policy to act like that:

• in front Block 1 000 000→2 ‑ 3 Can be used with multi-sign quorum (keys A, B, C).
• At / after Block 1 000 000→ only You can spend on another 2‑ of ‑3 quorum (keys x, y, z). The A/B/C path must be disabled.

Here’s an attempt at naive miniscript:

andor(
  ln:after(1000000),       // height check
  multi(2, X, Y, Z),       // “after” branch
  multi(2, A, B, C)        // “before” branch
)

But I believe after() You can add only conditions. You cannot permanently disable a previous A/B/C branch. Therefore, both 2‑3 quorums remain usable forever.

Is my understanding correct or is there something missing? Do I need a new opcode/softfork to “cancel” my previous spending terms?