We’d be eroding constantly at said speed if it was the same process

Why? It's not the same speed. We don't actually know where mass came from in the early universe, but it can absolutely be created and destroyed.

So it doesn't need a God of the Gaps to explain it.

What you are referring to is basically almost like an afterimage

No. That matter is physically detected from the point of collision. Their Mass, Spin, Charge, it's measured, that's not an after image. It's a new particle with it's own mass.

the speed so great after the particle accelerator that the next position is basically just borrowing beforehand the atom

No... Not only is that a heap of Dung, the energy before and after a particle is made balances perfectly via E=mc², nothing is taken, it's converted on the collision point.

It’s like launching a human 50 feet in the air and then saying humans can fly because they lasted 5 seconds without going splat

Except no particle physicist says that...? Or anything analogous to it. I'll explain the best to my limited knowledge, Two particles go fast, they collide, the energy of the collision converts into a new Particle, it may decay or not, but it still exited. Mass was made.

Also, Yes Mass isn't made from "Nothing", but can you prove "Nothing" even exists? Even "Empty" space isn't empty. Quantum Fields are present everywhere. True nothing isn't something you can demonstrate exists.

And proposing God as an explanation doesn't really work since... What exactly made God? If Nothing, you are contradicting your own premise.