"Debasement needs to be subtle otherwise it gets recognized for what it truly is — blatant robbery."

Modest, predictable debasement is not "robbery"; it is an excise tax on hoarding purchasing power. Gradual inflation encourages economic activity by making cash a wasting asset. That's why the Fed's idea of a "stable" currency is one that depreciates slowly.

Properly done, debasement has nothing to do with paying off the national debt, because the interest rate on that debt is negotiated in the market with an eye toward expected inflation. The debt is not paid off with cheap dollars; rather, it self-amortizes over time via the inflation portion of the interest.

When Treasury bonds pay less interest than the inflation rate, that just means that the market is willing to bear the (reduced) demurrage tax implicit in the bonds relative to cash. No one is "stealing anything from anyone," because everyone knows the rules of the game.