Delete does exist in the web vault’s kebab menu, both for individual items and for those that are “selected” for bulk operations.
To access from the browser extension (et. al.) Click on the entry to “view” it. The delete button is in the bottom right hand corner. Due to its “danger” and rarity of use, I am glad that delete is outside the normal workflow.
You are “out of votes” becuase you have not earned any yet. Spend a while reading (~30 minutes) and you will become a “basic user” instead of “new user”, earning you your 20 votes.