This is just one thing that I’ve noticed ever since my FaceID stopped working. It stopped working after using my iPhone for less than 30minutes while it’s raining and got a bit chilly in Fuji Rock a few months ago. Ever since then, it stopped working and won’t let me add a new face or even re-set up. I tried re-installing iOS and starting new but it’s still won’t work. My front-facing camera still works perfectly.
Anyway, back to the topic. Since then, I only use my 6 digit passcode to open my iPhone. At first, it was troublesome but I noticed that if I don’t really need to open my phone, I no longer do. So, my phone usage got even smaller. And since I’ve also reduced my notifications ever since I have an Apple Watch, I think I only interacted with my phone at least 1-2 hours a day.
Turning off your FaceID or TouchID might help you access or open your phone less. Works for me so far. Might bring it to an Apple Reseller next month and see if it will be replaced under warranty for free. But if not, I’m not willing to spend at least $400 for a replacement. Anyway, this set up is working perfectly for me as I use my phone less.