by mproudfoot » Tue Aug 02, 2022 7:06 pm
The OS Maps app does let you import gpx files - I do so before every weekend as a tertiary backup nav solution - not sure if you are talking iPhone or Android, but at least on iPhone, I can click on a GPX link (such as those from Walkhighlands), download it and then open it (selecting OS Maps as the app to open it in) then in OS Maps, it lets me name it, etc before saving it and and download offline mapping for the route - selecting the route whilst in the area will also show you where you are (and you can also follow the route, though I've never used it that way).
As you mentioned, there is a subscription fee, but it's under £30 a year which I feel is a reasonable fee for such a useful app.