I understand what you are saying about Matt 7:7, while some people interpret these verses as a promise that God will give disciples whatever they pray for, linguistic connections between these verses and other portions of the Sermon on the Mount suggest that Jesus promised that those who ask, search, and knock will be invited to enter His kingdom. The command to keep asking is tied to the promise of "good things" to those who ask in verse 11. In the Lukan parallel, these good things are interpreted as the Holy Spirit who transforms the disciple and makes him fit for the kingdom. Keep searching uses the same Greek verb as 6:33, "Seek first the kingdom of God and His righteousness." Since the word door is not in the Greek text of verse 7, and because ancient people knocked on gates as well as doors to request entrance (Ac 12:13), keep knocking likely refers to knocking on the gate of the kingdom (mentioned in vv. 13-14).
Jesus tells us to pursuing God. People often give up after a few halfhearted efforts and conclude that God cannot be found. But knowing God takes faith, focus, and follow through, and Jesus assures us that we will be rewarded. Don’t give up in your efforts to seek God. Continue to ask him for more knowledge, patience, wisdom, love, and understanding. He will give them to you.