Add me for needing this tool as well. In fact it's a primary reason that I use a digital journal, I need to find notes that I've made for myself in the given time I need them. I use dates, names, times, verbs, phrases, etc. in order to highlight through the growing data. I usually do find them with the search tool built into the app but it takes much work. The more entries I make the harder this process gets.
Even with the amount of work it takes, search and tags do help me find what I need when I need it.
Just a quick tip for those interested: if your investigation gets tough enough you can export your data and search through it with a word processor. And if you really want to be impressed you can take your exports and place them as datasets for language models so that you can just chat and ask what you want to know about your data.