I use openstreetmap.org maps on my Garmin for walking. (I do carry an OS too, but only for emergencies).
Sometimes OSM has far more accurate pathing (alhough by no means always), and if not, you can add paths yourself. When you edit with OSM, the satellite info is overlaid so it’s easy to draw paths accurately, and you can also import tracks from your gps and have them overlaid too.
Talkie Toaster does mapsets drawn from OSM that load onto Garmins and many other makes of gps, as well as pc software like Basecamp.
When I walk somewhere that has poor OSM mapping, I enjoy spending an hour or so improving it for others that come after. It’s quite an addictive sub-hobby to be done in a nice and warm seat with a cup of tea, once the hard walking’s done. And by doing so, I re-live the journey.
And yes, all this is free. Totally. If it sounds interesting, take a look and get involved.
(In defence of OS, I love them and find reading them inspiring. Also paths “drift” over the years, sometimes hugely, which may explain inaccuracies on old maps, and I don’t think OS update footpaths so often)