True grace is only true grace if it I unconditional
Your position is universalism. Everyone is just forgiven, slate wiped clean. The only problem with sin is God calls it sin. Take that away and everything is just dandy.
Following Jesus is always conditional. Do you really think the temple, Israel, the purchase from slavery, the battles of people over who is faithful to God, Gods grace and patience and final judgement, are summed up in, you are just forgiven.
Let us start with the first condition.
1. You must believe
If you do not have belief in Jesus, that he is the Son of God, given for all, for the forgiveness of sins, you faith is in vain.
This is a personal action, a conviction. Now we could argue as Jesus says, unless the Father calls you, gives you birth from heaven, you cannot even answer, but from our perspective, you must believe.
2. You must act
Repentance is admitting your failure before God for your wrong actions and committing to follow Jesus and His ways.
Without walking in Jesus's ways there is no change or being in the Kingdom. It is the fruit of faith.
3. A changed heart
You will find your heart has changed, things become different. You can sow to this heart or sow rebellion which will destroy the heart and kill your relationship. The parable of the vine demonstrates this exact principle, over time not abiding in the vine will destroy you.
4. Fellowship
Actively abiding in the vine, in the word, in the Spirit, in Praise and worship, in intercession powers everything.
Now these do not justify the believer, but they are a chosen walk, without which most cease to be in the Lord.
Somehow your "but" throws this all away, so I would call it heresy.