I get that you’re not storing something long term, but you are still storing it even if it is short term and thus presenting a risk. And you are still sharing secrets between applications thus presenting a risk. And all your suggestion is doing is offering a kludge around a solution you’ve already said is crappy, rather than switching to a robust and battle tested solution that literally every other platform already supports.
If you want to pass secrets securely between applications then you use a secrets manager. It’s how Linux and macOS work. It’s how secure systems in the cloud works. And thus it makes complete sense for Windows to follow suit. We aren’t talking about some theoretical concept here. It is absolutely how passing secrets between applications should be done.
If you have scepticism about this approach then you need to read up in this topic rather than pushing for a half baked kludge around something you’ve already acknowledged isn’t fit for security.
Sorry if this sounds blunt but this is a solved problem you’re trying to re-engineer and your solution is worse than the industry standard in a number of ways which I’ve already highlighted. And ironically it isn’t even just worse for security but also worse for usability well (you’re creating administrative overhead with the user approving safe applications. This wouldn’t be needed with a secrets manager since each application only has visibility of its own enclave). And if you remember back to your first post, usability was the entire reason you designed this solution in the first place.