Avoiding async in order to avoid parallel database calls literally only makes sense if you're choosing between blocking/non-blocking on a single process on a single server instance. The second you scale up to use multiple processes/threads and/or multiple servers, you're going to be dealing with concurrent db calls regardless of whether or not your code is written as blocking or non-blocking.
So not only are you saying that you insist on writing blocking code in order to avoid parallelism, but you're also saying that you'll limit yourself to a single execution process. Assuming a 50ms round trip to the db, you're basically setting a best case scenario of ~20 requests per second.
So not only are you saying that you insist on writing blocking code in order to avoid parallelism, but you're also saying that you'll limit yourself to a single execution process. Assuming a 50ms round trip to the db, you're basically setting a best case scenario of ~20 requests per second.