Listener (lsnrctl) reload vs stop/start
reloading your listener will allow listener to take new changes (configuration) without stopping it, and it will un-register\register dynamically registered DBs.

stop will stop listener completely by disallowing new session to connect to the database remotely.

start will start listener and this will allow users to continue working on the database.

for me I usually use listener reload for production to make sure I dont have any downtime during working hours. stop\start incase we need to perform some maintenance