Mongodb error after db repair command
OK.. You have managed to get your self in middle of mess. As it says:


  UnsupportedFormat: Unable to find metadata for
  table:index-3--243586308771972589 Index: {name: id, ns:
  admin.system.version} - version too new for this mongod. See
  http://dochub.mongodb.org/core/3.4-index-downgrade for detailed
  instructions on how to handle this error


Index meta information "says" that it's version is beyond >3.4, what of course it cannot be. Problem index is index of _id at admin.system.version -collection. We can "loose" this collection without problems because we know exactly what we have there. It would be easy, if you had enabled 'directoryPerDB' and especially 'directoryPerIndexes'.. BUT there is tool to fix things in wiredTiger, what I have never used but here is story how to do it. Find out files of admin.system.version -collection, rename those files and try to start mongod again.