How can one atone for purchasing a house through a loan from an interest-based bank due to its lower interest rates?

Your engagement in usurious transactions is forbidden. Allah has warned those who engage in usury of war and annihilation. Allah Almighty says: "O you who have believed, fear Allah and give up what remains [due to you] of interest, if you should be believers. And if you do not, then be informed of a war [against you] from Allah and His Messenger." And "Allah destroys interest and gives increase for charities." You must repent and regret, and resolve not to return to disobedience, and it is obligatory to limit yourself to paying only the principal without the usurious interest, if possible.