Acer Aplha 12 doesn't turn on. Black screen and blue light constantly on power button

A few days ago I noticed my tablet doesn't turn on. I didn't use it for a couple of weeks and I don't really remember what was it's state before putting it on the safe place.

The screen is completely black, no Acer logo showing up. The power button is constantly blue.

I tried multiple suggestions ok this forum.
1. "Hold the power button until it turns off (black)" - it didn't turn black even after 5 minutes of holding it pressed.
2. "Let the tablet with the blue light for a few days to drain the battery." - that was the only option I could actually somehow change the power button state, obviously. After 3-4 days it turned off completely. I plugged the cable and the button turned red (seems like charging). After 2-3 minutes I pressed the Power button, then it turned back blue and here we go again. The same problem. Nothing actually changed.
3. The I left the battery to drain back after a couple of minutes, plugged back the cable and tried pressing Power button + volume up - didn't work.
4. Repeated #3 but with the volume down - also didn't work.
5. I tried also using a Logi wireless keyboard with the USB dongle and press Delete, F11, F12 keys (to get into BIOS). Nothing worked.


So, all of these possible solutions didn't work.

I'm thinking to get my screwdriver on it (I have experience with my older phones so, no issues ok this part. Also there are some YouTube videos and a few recommendations from other users in this forum how to open it without breaking the screen).
I'm thinking to reset the BIOS settings how you normally do on a PC motherboard, but I still don't know how can it be done on this device.

Can someone help me please with some advice for this problem. I have an important document on it and I don't want to get off the SSD and throw away the rest.

Acer Switch Alpha 12, i5 processor.

Thanks in advance.