The promises in the Mosaic old covenant were conditional- Obey God’s law-blessed. Disobey- cursed. Forgiveness was conditional- obey the sacrificial system in order to be in right standing with God- disobey- face God’s judgement.
The promises in the new covenant are based on one condition- believe and receive Jesus Christ for the forgiveness of sin- obey what God said in regards to His redemptive plan- disobey?
The sacrifice of Christ was a one time offering- after His death there no longer remains a sacrifice for sin- to ask for forgiveness after receiving Christ is worthless unbelief.
I John 1:8-10 is a testimony to the unbelieving world concerning Christ- verse 9 is not meant to be used as a sacrificial system based on law. We are no longer under law but grace. These verses were not written for believers, they are about salvation.
We must get out from underneath a belief system that kills us.
I know this is harsh, in fact I don’t even like talking like this, but if I have to verbally slap somebody in order to bring them liberty that’s what I’ll do.
Suggestion regarding I John 1:9, instead of asking God for forgiveness when you blow it, start thanking Him for the forgiveness you already have.
I can assure you that this type of obedience will open the floodgates of divine power into your life.
May you find rest for your soul!