Good day, SJ
I contend that if he wanted to have Mercy on all he could in fact choose to do that.
What do you mean "if" He wanted to have mercy on all? Scripture says He does. Did you not read the passage I referenced? Are you views based on scripture or something else?
Romans 11:30 Just as you who were at one time disobedient to God have now received mercy as a result of their disobedience, 31 so they too have now become disobedient in order that they too may now receive mercy as a result of God’s mercy to you. 32
For God has bound everyone over to disobedience so that he may have mercy on them all.
It's not a question of "if" He wants to have mercy on all people. He does. Scripture clearly teaches that. The question is why does He not have mercy on all people? We know it can't be because He doesn't want to. The only viable explanation is that He makes people responsible to choose whether to humble themselves and repent and believe or not in order to receive mercy. He doesn't force Himself on anyone. He demands that people repent willingly (Acts 17:30). How can it be genuine repentance any other way?
Do you believe he wants to and he is unable to do so?
No. He wants to and is fully able to do so, but He requires people to humble themselves and repent and believe in order to receive mercy.
Read this parable:
Luke 18:9 To some who were confident of their own righteousness and looked down on everyone else, Jesus told this parable: 10 “Two men went up to the temple to pray, one a Pharisee and the other a tax collector. 11 The Pharisee stood by himself and prayed: ‘God, I thank you that I am not like other people—robbers, evildoers, adulterers—or even like this tax collector. 12 I fast twice a week and give a tenth of all I get.’ 13 “But the tax collector stood at a distance. He would not even look up to heaven, but beat his breast and said, ‘God, have mercy on me, a sinner.’ 14 “I tell you that this man, rather than the other, went home justified before God. For all those who exalt themselves will be humbled, and those who humble themselves will be exalted.”
Notice here that the Pharisee and people like him "were confident of their own righteousness and looked down on everyone else" including people like the tax collector. The tax collector, contrastly, had no confidence in his own righteousness and didn't look down on anyone. Instead, he humbled himself and acknowledged that he was a sinner while asking God for mercy. Then notice that Jesus said "For all those who exalt themselves will be humbled, and those who humble themselves will be exalted.”". Read that again. It doesn't say "For those who can't help but exalt themselves will be humbled, and those who God humbles will be exalted". People are expected to choose to humble themselves. God doesn't do it for us. We are expected to acknowledge that we are sinners who can't save ourselves and need God's mercy. Your view that God has mercy on some and not on the rest for reasons that He only knows is not supported by scripture, including this parable. It's very clear how God decides who to have mercy on and who not to have mercy on. He has mercy on those who humble themselves. All people are required to acknowledge their sins and their inability to save themselves while trusting Jesus/God to save them instead.
I will have mercy on whom I will have mercy. Mercy is a verb he "wills" to do it.
That's right. But, how does He determine who to have mercy on? That's what you said nothing about here. Scripture tells us how He determines that. But, I would imagine you say it's just a mystery as to how He determines that. No, it is not. The parable in Luke 18:9-14 shows us how He determines that.
Now I guess it would be fair to say he has Mercy even to those he created that he knows he would condemn. Him waiting to do so and sustaining them would be an act of Mercy, would you agree?
That's not what we're talking about here. We're talking about salvation. We're talking about Him having mercy on people and saving them from the penalty of their sins. That is what the passages we're talking about relate to and not to Him having mercy on people in some lesser sense.