What kind of APIs are you writing that don’t involve db lookups or calls to other services?
The only thing async io gives you is scalability of many MANY concurrent io operations. You have to either be pushing seriously large traffic or doing a lot of long running websocket/sse/long polling type requests.
The only other use case is lots of truly concurrent io within one request/response cycle. But again that is unusual, most apis have low single digit db queries that are usually dependent on one another removing any advantage of async.
Why just "within one cycle"? What about situation where you spend 1s in single db query and are 100ms cpu bound during request handling?
The point is asyncio is to have find grade control of yealding.