How can get back to watch face whilst in a walking activity?

Just adding to the already mentioned, your watch face will timeout and switch back to the activity after (I think) 2 minutes.

So yea, it's probably best to setup a page with all the data you want to see while recording. You wont stay on your fancy watchface.

There are a few ways to do this. The easiest two ways are:

• Disable "lap" key in the activity settings. Then, as long as you're not in a training workout or multisport event, pushing the back button will go to the watchface. And pressing it again goes back to the activity.
• The 2nd and more robust method is to set a hotkey to point to the Watchface.  I use the start button. So, if I hold the start button, it goes to the watchface. And if I press it again (not hold it), it goes back to the activity.

This hotkey is already set as standard, "long press" of the lap button, no need to disable lap function. And already answered by OnlyTwo.

And no, there is no way to do this as you won't remain on the watch face as the topic creator probably wants to do.