I have a iPhone SE 32GB as a backup phone. Works with Carplay Google/Waze navigation, and no lag. You might encounter on rare occasions where the tablet in the car will crash or disconnect with Carplay but this happens on my iPhone 7, too.
I have a short video of my iPhone SE running Google Maps with offline maps while cellular data is off from earlier today. The iPod Touch wouldn't work because they don't have a GPS receiver chip.
https://drive.google.com/file/d/1Nupk1DCDn23U-tYElT8pipVBGy1NNOnr/view?usp=sharing