I recently flashed Ubuntu Touch onto a Pinephone and was quite impressed how advanced it generally is. One thing however that is beyond me is why there is no global screen button or swipe motion allotted for "going back", such as on Android. For reference, a post from earlier this year that tackled this very question but kind of went nowhere: swipe to go back

I understand that, in theory, you could leave it to the app developers to each (hopefully!) implement some kind of go-back functionality within their specific apps, but a global back button/swipe motion would make life way easier and put the user back in control over badly designed workflows in apps. Reaching a dead end in any given app, swiping to close it (two motions) and re-opening it to get back to where one step BACK would have taken you (for example the list view in a video app liked Dtube), seem like tedious workaround to be honest, not to mention having to remember exactly where you were in the app. Would it be complicated to build such a global go-back feature and make it work in existing apps?