I have coins I acquired back in 2014 and haven't touched them so far. That's like 11 years. 
Self-control at its finest.
Although I too don't think it was stolen, you're wrong.
nSequence = 0xFFFFFFFE, so no RBF, so nothing the owner could do once the tx is broadcasted.
doesn't matter if it gets mined in a block or two, or 20.
nSequence = 0xFFFFFFFE, so no RBF, so nothing the owner could do once the tx is broadcasted.
doesn't matter if it gets mined in a block or two, or 20.
Once the tx is broadcasted, it gets in the mempool, where it lives until it gets written in a new block. If the block that has it included gets mined, then indeed it's impractical to try to revert it.
But as long as the tx is in the mempool, you can definitely try to cancel it or speed it up.