What’s the easiest way to make Bitcoin Core acknowledge and signal transaction for customized descriptor?

The issue is that I’ve a customized witness script and I need Bitcoin Core to have the ability to signal transactions for that script.
Initially, I wished to create a brand new commonplace deal with and use its key for signing, however this fashion bitcoin core cannot compensate for the identical public key it already is aware of. This problem: https://github.com/bitcoin/bitcoin/points/27336

So, now I need to use the personal key of the present pockets with the hd-path.
But it surely requires unusual manipulations like:

1. listdescriptors
2. Take random xpriv
3. Add this xpriv with some particular hd-path to new descriptor
4. Import this descriptor
5. Then I can signal

I ponder is there a greater approach?
Descriptor for an instance:

wsh(or_d(pk(),and_v(v:pk(),older(timelock))))

Additionally, what to do if the personal key within the chilly pockets?