I’ve got the Garmin Touring Edge, it comes with Open Source maps that are really good, even off road.
I have a copy of the Garmin OS maps on the same mini sd card, the device allows you to choose which maps it uses on the fly, the OS ones are a little hard to follow on such a small screen so normally use the open source ones.
It does full turn by turn routing etc and it’s ace, use it all the time, think I paid around £150 for it.
Great as reassuarnce when out in the hills. Although like any GPS I’ll still pack a paper map when exploring proper hill country.