Assume a client calls an asynchronous RPC to a server, and subsequently waits until the server returns a result using another asynchronous RPC. Is this approach the same as letting the client execute a normal RPC

This approach is not the same as letting the client execute a normal RPC

Explanation:

This approach is not the same as letting the client execute a normal RPC and this is because an asynchronous RPC sends an additional message across the network after the initial call/message is sent by the sender to the client. this additional message sent through the network is directed towards the sender of the initial call/message as an acknowledgement of the receipt of the initial message by the client .

synchronous RPC is made of two asychronous RPCs, hence the client executing a normal RPC  will not establish a reliable communication between the client and the sender as asynchronous RPC would

you have to first get good enough where you are an ace or master, then some of the creators could make you a mod. (this is pretty hard to do though)