No question that He did harden some human hearts - the real question is whether He continues to do so under the New Covenant...
Read Romans 1:18 - 32. Seems it gives some clarity to the issue.
Continuing in sin once warned by God (as Moses warned Pharoah) results in a hardening of one’s heart - a willful blindness perhaps. God made man this way - the more he resists any revelation from God - the blinder he becomes, and the harder his heart becomes.
The converse is also true. The more one receives revelation from God, and acts upon it, the more light is given to one.
Did God have an active part in this? Scripture clearly says so. BUT, it does not exclude man’s part. And his reaction to God’s truth (light, revelation) will always bear the fruit of man’s reaction.
What is God’s part and what is man’s part is a mystery that we probably will never comprehend until we see His face and are with Him.
Our insisting on comprehending something beyond us results in our taking one of two sides: The hyper-Calvinist ultra-predestination view, or its opposite - that man decides everything. Both are error. If they exclude the other.
Scripture clearly presents both as being concurrently true, and our finite minds cannot comprehend this.