I don’t know about other people, but for me, if I want to be the most productive, it’s essential to have systems in place to help stay focused and remind me what I should be doing. Lately, I’ve been using an app called Be Focused for that. It’s a fairly basic app for doing Pomodoro style time tracking — although, if the idea of a “system” scares you, the app never calls it Pomodoro. I’ve tried a few of these in the past, and this is probably the best one (and the most maintained).
You tell if how long you want your interval and break periods to be, and it does what you’d expect by timing and transitioning between those periods. The one more advanced feature is that if you pay for the pro version (or get it on SetApp), there’s an integrated to-do list, which is nice if you want to reminders of what you were actively working on.
I’ve mostly used the Mac version because that’s where my work happens, but it’s also on iOS, and they do sync. Be Focused is available on the App Store and in SetApp. If you find yourself needing something like this, it’s a good option.