You cannot earn or merit Salvation in any way but that doesn't mean that you are not expected to obey and follow Christ in order to stay on course.Please, the OSAS doctrine goes hand in hand with the other marketing ploys that Protestant churches have come up with ever since the 1930s when they accepted contraception. The doctrine of OSAS sells the sizzle and that's the way Satan keeps people focused on what Bonhoffer called cheap Grace that is in essence just a way to whistle past the graveyard. It completely ignores the FACT that while no one can pluck you out of the hand of God you can jump right out on you own any time the same way the first followers of the heresy of Core left His hand.
The Catholic teaching that there is a difference between venal and mortal sins is soundly based on Scripture and makes it clear how one is to behave as a Christian in order to remain in a state of Grace. Non-Catholics can each decide for themselves that whatever they enjoy is harmless and only those things they don't enjoy, or don't want caught enjoying, are to be avoided. In 1929 all forms of contraception were a sin, shortly thereafter there was nothing wrong with contraception.
It's the same with queers being ordained or married to one another. The majority wants to ordain queers and allow them to be married to one another so the Scripture is reinterpreted to permit what the market wants. Gambling, tattoos, premarital sex, cohabitation before marriage, and a host of other things that were preached against as being sins only thirty years ago are now all just fine and fall into the big marketing bin labeled, "Christian liberty".
Protestantism always adapts to whatever the market demands. Individuals begin to ignore what their church preaches so the churches either reinterpret a verse here and there or simply say that this or that isn't clearly called wrong so it must be OK even though they argue exactly the opposite when it suits their marketing plan.
By your line of reasoning, the will of the Father that none should perish prevails anyway no matter what any of us do so we're all saved and headed for heaven sooner or later anyway. Which is exactly what OSAS boils down to, just totally fatalistic Calvinism except with everyone counted among the elect and incapable of being anything but one of the elect because it's the will of the Father than none should parish.
In other words, the heresy of Universalism.