Maybe you should adapt your expectations for your 20$ monthly subscription. That's by far not what it's worth
I burned already through over 100$ in a single day with per token payment for heavy usage. I don't have any issues with Claude not working or being "nerfed". It just works
The convention for internal "Query" routes in my company is just a Post with a path starting with "/queries"
This is taken care of in eg. our retry middleware.
Not as good as a standardized idempotent Method, but good enough for the time being till they finally approve this as RFC