Hi again
I now bought the Galaxy Watch anyway. Switching phones is in fact reasonably doable when using Samsung backup. Of course, app settings are not restored (including Health data, which is ok when using Samsung Health on the phone, too), but the important stuff like watchface, widgets and app order are. So I'll do that for longer trips with another phone, and for shorter ones, I'll just go without connection (don't need mail notifications on a hike, anyway). [that's nonsense, of course, as Locus won't work then - so either do the reset-switch-cycle or go w/o Locus on watch]
Apart from that, I find the Locus app very nice, but I agree with others before that the recording mode should have a map page, too. Going back to map and then back to the dashboard again is just the kind of annoying actions that you don't want to do on a trip (back button - tap the small icon and then again). Please consider, as proposed before, to add a zoomable, non-movable map screen as part of the dashboard. Thx!