Testing against server version 4.9.0-alpha-1124-ge369908, I locally see dropping a non-existent collection and then explicitly creating it take ~10 seconds if each node in the replica set has the requireApiVersion parameter set to "1" and both the "drop" and "create" commands are run with majority write concern. If the parameter is not set, both commands execute in under one second.
I've reproduced results using this Python script: https://gist.github.com/divjotarora/29c523b726933192d563b823a2f8abbd. Running "python3 main.py" will execute both a "drop" and "create" command. Additionally, "python3 main.py --setParamter" will first set the requireApiVersion parameter to '1' on each node in the cluster.