Unspendable keys in descriptors

The crux of the problem lies in the mismatch between the natural order of extended public keys (xpubs) listed within wallet policies and the left-to-right sequence found in descriptor templates. A provided example illustrates this discordance, where a descriptor template is defined as "tr(_,{pk(@1/**),pk(@0/**)})", yet the associated keys are arranged as ["xpubA", "xpubB"]. In this scenario, the expected left-to-right ordering does not align with the actual order, which should be pubkeyA||pubkeyB.

The discussion suggests that if the placeholder _ used to denote a deterministic NUMS key is exclusively determined by wallet policies, then adopting an approach native to wallet_policy would be more favorable. This recommendation hints at a resolution where the inherent structure of wallet policies would guide the organization and referencing of keys, potentially alleviating inconsistencies brought about by the current system's design.