How to compare with unix time (timestamps) and date time?

I want to search for tasks “DONE” on certain days. So I created query like this, but it got nothing. I think the reason is that “created-at” generates timestamp format, it may not be comparable with date format. So I want to know how to convert date format (yyyyMMdd) to unix time or make them comparable. Can somebody help?

    :title "find done tasks"
    :query [:find (pull ?b [*])
          :in $ ?start ?end
          :where
          [?b :block/marker ?marker]
          [(contains? #{"DONE"} ?marker)]
          [?b :block/updated-at ?v]
          [(>= ?v ?start)]
          [(< ?v ?end)]
          ]
    :inputs [20220504 20220505]