I see! Search is there though. Top right of the calendar you can search on event/todo level through all days. And in the general notes section you can search for full notes. Inside a note you can do text search. The tags currently don’t do much in the calendar though.
I’m using NotePlan also as a journal. Below all the todos and events, I create a title “## Journal” and just write my stuff there. This way you can quickly review your days — todos and journal. I usually review my last week on a sunday. Helps to clear up anything, which got stuck during the week.