Has God ever accepted a defective sacrifice?
Has God ever accepted a spotted, unclean, defiled, blemished, blind, lame, or sick sacrifice?
"Whatever has a defect, you shall not offer, for it will not be accepted for you" (Leviticus 22:20).
"But if it has any defect, such as lameness or blindness, or any serious defect, you shall not sacrifice it to the LORD your God" (Deuteronomy 15:21).
"You shall not sacrifice to the LORD your God an ox or a sheep which has a blemish or any defect, for that is a detestable thing to the LORD your God" (Deuteronomy 17:1).
"'But when you present the blind for sacrifice, is it not evil? And when you present the lame and sick, is it not evil? Why not offer it to your governor? Would he be pleased with you? Or would he receive you kindly?' says the LORD of hosts. 'But now will you not entreat God's favor, that He may be gracious to us? With such an offering on your part, will He receive any of you kindly?' says the LORD of hosts. 'Oh that there were one among you who would shut the gates, that you might not uselessly kindle fire on My altar! I am not pleased with you," says the LORD of hosts, "nor will I accept an offering from you'" (Malachi 1:8-10).
Roman 12:1-2 beseech (beg) living (not dead) sacrifice (God never accepted a spotted sacrifice) not worldly, mind (heart) prove (Bible authority) perfect (God is perfect) we must be perfect.
Matthew 5:48 same Greek word (teleios) whatever God is, I must be the same.
"Therefore I urge you, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship. And do not be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what the will of God is, that which is good and acceptable and perfect" (Romans 12:1-2).
Partial quotes will only give you partial answers that can be misleading. Yes, we are to be living sacrifices to God. Here Paul is not talking about a physical sacrifice but a spiritual service of worship to God, done such that God finds it acceptable. Like the Israelites, we cannot offer worship to God while being involved in sin. The unholy cannot be mixed with the holy. Nor can we mix the ways of this world with the ways that God has taught. It is God's ways that are good, acceptable and perfect.
This is why Paul stated that Christians cannot be involved in sins, such as fornication, and expect to have God accept them while they remain in sin. "Flee immorality. Every other sin that a man commits is outside the body, but the immoral man sins against his own body. Or do you not know that your body is a temple of the Holy Spirit who is in you, whom you have from God, and that you are not your own? For you have been bought with a price: therefore glorify God in your body" (I Corinthians 6:18-20).
Yet, at the same time, we must understand that we sin. We should never remain in sin, but we will not be sinless. "If we say that we have no sin, we are deceiving ourselves and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:8-9). Therefore, when we do realize that we have sinned, we change our behavior and ask God for forgiveness so that we can continue to worship Him.
So while God's ways are perfect, we are not consistently perfect, but we strive to follow God and become better people.