Cannot unlock my Samsung phone because "Keyboard stopped working"

Hi,
I have a serious trouble with my phone.
My phone's model is sm-g5108q(SAMSUNG G5108Q Galaxy Core Max).
It is manufactured in 2014 and of course it's old phone.
Oneday when i power on my phone, i can't input password because keyboard is not appearing.
It seems samsung keyboard error.
Password type is normal password(not pin,pattern,face,fingerprint)
I reset my phone lots of times, but always the same results.
I can't perform the Factory reset becauseof loss of data.

I googled my issue all day long, so i found solution. That's the way to use usb-key board(with otc cable)
After i connected usb-key to the phone (with otc cable), but nothing happend, I disappointed.
I tried it on other phone, usb-key works well on lock screen on that phone.
I looked thorugh my phone,omg, my phone turned into Emergency mode(i don't know the reason).
In Emergency mode, it didn't permit to connect other device to save battery.
I googled again to find the method to disable Emergency Mode.
On Recently produced phone, after pressing power button, there was a menu "Enable/Disable Emergency Mode".
But my phone is old one, so in order to disable Emergency mode, i think i should login my phone.

So i can't do anything.
To use usbkeyboard, i should disable Emergency mode.
To disable Emergency mode, i should login phone.
of course, i know my password.
Please help me, i will appreciate any solutions or advices.

Can you boot into Recovery for a Cache Partition wipe? If so, that may help.

Booting into Safe Mode may also be worth trying.

Thank for belodion's reply.

I have tryed,but still same problem.

Are there any solutions?

If anyone solve my problem, I'll giive you bonus wit BTC.