My new phone will probs arrive tomorrow and me and mates are going on a vacation to Germany next week.

Currently using nearly all bandwidth/ram of one of my dedicated servers to download maps for offline use (OpenStreetMaps) and convert them to formats OsmAnd can use.

No need for google maps ❤️

I'd say Linux but seen that around a lot so I'll go with another favourite:

OsmAnd(+)

It's basically an offline navigation app which works with downloading maps offline and then you can use navigation without Internet (gps though of course).

It's very easy to use, looks okay enough and no fucking tracking at all. I was in Switzerland recently without any service (my friends didn't have service either and their navigation relies on Internet) and this fucker saves us big time.
Not saying that there aren't any other offline navigation apps but this one is awesome imo.