Whosoever means all who will believe as it is not limited as God so loved the world, that he gave his only begotten Son that all have the opportunity to come to Christ.
Where do you find in the Bible that "whosoever" means that "all" have the opportunity to come to Christ? Could it be at least theoretically possible, that Christ's purpose was to specifically save only those intended by God to salvation making them the "whosoever(s)"? Think about the implications of your point of view: those who are unable for any reason to believe, such as those who will not have opportunity to hear the true Gospel; those who are mentally deficient that cannot perceive the Gospel; those who die in the womb, ETC, according to you, everyone in those categories, can never be saved - so, based upon that please explain what their spiritual end will be, since apparently Christ is of no benefit whatsoever to them, even though (as you say) Christ died for them too. This means that if Christ sacrificed on their behalf, and fully removed their transgression, yet they can never find forgiveness. I believe your conclusions therefore to be biblically, theologically, and logically unsound.
Further, and even more alarmingly, your point of view takes away the role of Saviour from Christ and makes it the responsibility of each individual to achieve on their own.
Consider the contradiction your interpretation raises when we compare John 17:9 to 3:16. In John 17:9 we read:
[Jhn 17:9 KJV] 9 I pray for them:
I pray not for the world, but for them which thou hast given me; for they are thine.
Jesus tells us in the above verse that He prays not for this world - the world that you say the Father so loved - supposedly including everyone- yet He prays not for it, but only for those whom the Father has given to Him (and vise versa), for they alone are the ones the Father claimed.
Compare to John 3:16:
[Jhn 3:16 KJV]
16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
We can see by comparing these two verses, that the "whosoever" cannot be a group of "all" people who inherently comprise it. Nevertheless, according to you, from that group of "all", per you, the only ones who can be saved are those with the intellectual ability that can reason their way into a faith in Christ.
[Jhn 3:17 KJV]
17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
In John 18:38, Jesus informed us that His kingdom was not of this world.
[Jhn 18:36 KJV]
36 Jesus answered,
My kingdom is not of this world: if my kingdom were of this world, then would my servants fight, that I should not be delivered to the Jews: but now is my kingdom not from hence.
and
[Luk 22:30 KJV] 30 That ye may eat and drink at my table
in my kingdom, and sit on thrones judging the twelve tribes of Israel.
We know that God will destroy this world (Kosmos) along with everything in it, so then how would He be able to also save it (per your statement regarding John 3:16) and yet will have to at the same time, to destroy it (per 2 Peter 3:10 - 13)? So, based upon your understanding, how does God achieve both of these mutually exclusive events?
[2Pe 3:10 KJV] 10 But the day of the Lord will come as a thief in the night; in the which
the heavens shall pass away with a great noise, and the elements shall melt with fervent heat,
the earth also and the works that are therein shall be burned up.
[2Pe 3:13 KJV]
13 Nevertheless we, according to his promise, look for
new heavens and a new earth, wherein dwelleth righteousness.
[Mar 10:30 KJV] 30 But he shall receive an hundredfold now in this time, houses, and brethren, and sisters, and mothers, and children, and lands, with persecutions;
and in the world to come eternal life.
So, the world that God so loved which world is identified in John 3:16, is further explained in Mark 10:30. From Mark 10:30, we can know it is the world to come that is the one that God loves and is where eternal life will be found but it is not this current world.
It's kind of late for me now since I get up early, so I'm not sure that my post is entirely intelligible. I may therefore have to amend it tomorrow after I reread it. If you disagree with it (which I'm sure you will), or don't understand it, please let me know and I'll try to clarify.