Low-end, really?
The A13 in the soon-to-be replaced iPhone beats all Apple's laptops other than the highest-end 16" MacBook Pro. I can only imagine what the A14 in a thermally less constrained body can achieve, and I suspect the "low-end" laptops mentioned will actually be superior in all respects (speed and battery life) to the Intel ones. All apps submissions the App Store have been sending a LLVM Intermediate Language variant that can be retargeted to any architecture supported by LLVM, including arm64. Obviously, poor coding practices and assumptions can still cause the code to work incorrectly, but I would think the transition will be better than the PPC to x86 one was.