I do indeed trust in what God accomplished through Christ, and, in fact, I trust in Christ himself.
To paraphrase what you said: You trust in a given fact, that Christ died for all sins, and therefore yours. I trust in a given fact, that Christ died for my sins. You seem to think that yours is more sure, since it follows a logical sequence. But both depend on that fact beyond mere logic, that Christ died for sins. I don't wish to here get into the question of how yours is more sure, beyond mentioning that I don't think it is more sure. One thing I know is NOT more sure for me, in what you say, and I don't see how it can be more sure for anyone else either, is the trust in THEIR faith —how one is absolutely sure that in fact they DID 'accept Jesus into their heart' or any of the many ways it is described. Every disobedience mocks the veracity of that claim.
But predestination, and in particular, providence, gives one assurance beyond the faith one can have in themselves to have been of full integrity in their 'salvation decision'. My security depends on the act of God, your security seems to depend on your trust in the act of God. Further, my security realizes that even my very disobedience is part of what God has planned concerning my life, and is no surprise to him, but a step along the way, a 'teachable moment', and that, agonizingly, at Christ's expense. Your security, well, I can't speak for you, but I remember my thinking back 20 or 30 years ago, of separation from Christ, of doubt in my 'decision for Christ', at every disobedience. My assurance is WITHIN the faith given by the Spirit. Yours seems to be the trust in the integrity of your decision that day you yielded your heart to Christ. Brother, I don't mean to disparage the weight, the power, of that 'crisis' moment. I feel it more than you might think I do. But what YOU did is not itself salvific faith, but the result of it, which God's Holy Spirit did in you.
But I don't see the difference in object. In the end, we both trust not only what Christ did for us, but in Christ himself. Faith is not, then, only trust in a fact or in a logical sequence of thought, but trust in God himself, in either one.