I am not sure this has anything to do with certificate. If you just want to login in as a webuser, try to set -DNodeType=WebUser then you should be fine. Kafka is used internally by Pega platform for stream node.
Yep. Indeed nothing to do with that. I am not always running into this issue while start up my pega personal edition in different time. Perhaps it is the connection to pega server. I disabled the stream service which seems help.