is there an app that is like a garmin where you an load a map in to and follow the route?

Memory Map?

Orux Maps. Interface is a bit odd, still not got my head around it but is an awesome piece of software.

There’s loads. I use mmtracker, viewranger and orux maps

My Tracks by Google comes close to a Garmin experience. Won’t do quite what you want but worth installing if you haven’t used it.