Hello mihaido,
Read these links please, though they may not provide satisfactory resolution. It's just what Apple provides on this subject.
About Apple ID security questions - "Learn about Apple ID security questions, including how to set up or change your questions." - https://support.apple.com/HT201363
"If you forgot the answers to your Apple ID security questions" click here --> https://support.apple.com/HT201485
If you see the message "not sufficient information" read this link:
Security and your Apple ID - https://support.apple.com/HT201303
"Without proof of your identity via a temporary Support PIN and other carefully selected criteria, Apple Support can't help you perform any actions on your account." Unfortunately the solution they offer using a temporary PIN also requires knowing your security questions answers... Catch-22.
With that in consideration, "Contact Apple for help with Apple ID account security" click here --> https://support.apple.com/HT204169 If the online option does not resolve the problem I suggest trying to get a personalized response with a chat or telephone call. To talk by telephone: Contact Apple for support and service - Apple Support --> https://support.apple.com/HT201232
For other support options including those if your country does not have telephone support: https://support.apple.com/choose-country-region To chat, choose any topic, (not Apple ID) continue working your way down options until you find one with chat support, then ask to be redirected.
(Note: If your country is not listed, there may be a support option at the end of each region section for "other".)
It may ultimately prove very difficult to find satisfactory resolution to forgotten security questions (e.g., https://discussions.apple.com/thread/252410816 ). Apple is very strongly urging users to use Two Factor Authentication instead of security questions. --> https://support.apple.com/HT204915
