Just a quick note - now the OpenMTBmap features a winter layout for winter sports - it was better this way then integrating it into the hiking layout.
And if you need a Garmin Oregon 700 or Etrex 35 touch - amazon.de has them heavily discounted today for Black Friday. That's pretty rare to find them that cheap. Edge 520 is also really cheap - but I don't recommend it to be used with maps - it's simply too slow (edge 530/830/1030 are not on offer). If so the edge explore is also pretty cheap - it's better than the 520 Plus and for using maps it's pretty fine too. It's main problem - no compass/altimeter.
Wie kann man das Winter Lay out am PC unter Windows installieren?
Einfach auswählen im Installer aus dem Dropdown – ist der letzte Punkt. Siehe etwa Screenshot hier: https://openmtbmap.org/de/tutorials/install/
da fehlt Winter allerding noch.