Instinct Solar Tactical randomly powers off during activity

Posting this in a bout of frustration because this is the second instinct Solar tactical that I’ve swapped to (and mind you, Garmin Southeast Asia doesn’t give free swaps). Video is an example (I do not always have my phone in convenient reach to record a video as I often workout without it), but I’ve had my watch powering off randomly in the middle of an activity even with a good deal of battery left.

Updated the watch, turned off vibrate, hard/soft reset… trawled the forums and tried ever trick in the book but nothing has worked, short of throwing the watch out of my window.

Moreover when it dies in the middle of a run/ strength workout the watch will eat up either the last 200-400M of the run or the last set of strength work prior to it dying.
Any solid bit of help will be much appreciated, or else I might have to consider jumping ship to another brand. Thanks!

Click here to play this video