God gave those who follow Him a roadmap to follow. It's called the Bible. I believe each person who is saved is responsible to know what the Bible claims on every topic. And if one reads, studies, and seeks understanding from God about the Bible they will be given the knowledge they seek. And if anyone reads the Bible they will discover it covers sins under the category of being unforgiven. And they will see how David, in Psalms, dealt with sin in that type of scenario. And we will read how up to the day we die we could have asked for forgiveness of those sins.
So to those who claim to be followers of God but never study the Bible, I don't believe they have any excuses before God. I also don't believe any doctrine promoting there's not a need to ask for forgiveness of unforgiven sins have any excuses before God.
God gives the average follower of Him many chances to read the Bible and educate themselves. I don't believe in doctrines that includes excuses because they promote being a Lazy Believer in God. And I see nowhere in all of the Bible where anyone who followed God with a purpose was ever lazy about it.