I cannot stress enough the word immediate. Delayed reports (after a week, after a day, or whenever I check) sure give a bit of reality-check and insight on what to change (usually only the first time) but were not useful for actually implementing these changes. (I have ADHD if that matters. For some people insight might be enough.)
Qbserve displays constantly the current productivity score. I had a love&meh relationship with RescueTime (since it does not offer a way to display productivity tracking all the time), but after composing it with a link to report on a new tab (my most common way of procrastination), it was a game-changer.
A small note - if you prefer something more private, and open-source, there is https://github.com/ActivityWatch/activitywatch (I use it as well). Not as polished, but clearly logging well, and it has Web UI on localhost, thus can be used with Custome New URL Tab as well.