iPhone unavailable, lock down timer stopped

I am using iphone 16 pro max (for 6months), 2 days ago the touch screen was slow responding and yesterday the usual swipe up & face recognition to unlock the screen stopped working. From there, below are the steps I went through;

1. I switched off and on, then passcode was requested, but the screen doesn't respond with finger touch.
2. I noticed long-press on signs/menu is recognized(ie if hard press on emergeny button, the word has a square frame around it.
3. I figured double tapping worked to enter numbers so I entered passcode numbers 2 times each.
4. After a correct passcode, the screen goes to stand by screen where you need to swipe up (by this time, I had to double tapp the bottom white bar)
5. Over several wrong passcode entry, (because double tappings were not responding quicky by this time) lockdown timer was set and set for 3 hours at the end.
6. I waited but noticed the timer stopped working as of 2hours and 39min remaining
7. You can see the current situation in the attached video (mind I use Japanese, it says "iphone unavailable, try again in 2 hrs 39min.
8. Network is lost, sound off/on, volume up/down alone does not work. Side switch and volume button together to switch off works fine.

Went to Apple shop today but the staff can't do anything unless the phone is unlocked. I wanted to ask if anyone encountered a similar problem? I wanted to ask before I had to set my phone to factory mode(erase everything).

Thank you.

https://youtu.be/Eyk2dREaJmg

the voice in the video is normal speed, not time lapsed video.