This could be keyboard layout issue as you think. If you have installed Windows in language 1 but later you have changed to language 2 inside Wndows then it's quite possible that sing-in screen use different language that what you use when creating that PIN. Do you se language selector on bottom right cornet of sign-in screen?
When Shift + 2 doesn work try to use ALTGR+2 instead.
If you can sign-in then open Control panel / Region, select Administrative tab and click Copy settings.
Select both options in Copy your settings to:
That make Windows and sign-in sceen use same language / keyboard settings.