Watch Broken at the hinge

I have the Fenix 5 Quatix, which is made to look highly durable, especially with my strong & heavy metal Garmin watch strap. Just like many in this thread has stated, I just noticed it one day when I went to change the strap from my metal one to my silicone one that I prefer to use when I go swimming. After doing a double take, the 'damage' on mine appears the same as that of AndrzejLu  which shows that the end of the hinge has fractured off, indicating no sign of force from the watch, but instead some reaction to either external force just on that corner, or that the material was simply weak, and a stress fracture caused it to simply become brittle and break off.

Since I categorically know that I've always looked after it, I don't do any manual labour, and it barely has a single mark on it (except a bit of regular dust in the gaps!), and I'd certainly know if it was banged as I never take it off my wrist except to change the strap or to charge it up every week or so, that it MUST be a material quality related issue.
The only form of abuse it gets (if we want to label it as such) is when I (regularly) go open water swimming in temperatures of around 5-10 degrees Celcius, so it may get a bit of a cold water shock, and this temperature fluctuation could perhaps cause stress-line fractures in the material. It may explain why the material became brittle, and then the rest could be done just by strap movement when simply resting my arm on a desk while typing.

Although it may answer the question of how a well treated watch could suddenly break at a critical point, the hinge, it clearly does not explain what to do about it!
When I bought it, over the internet, I thought it was metal, and not a plastic/resin type material which cannot be fixed, and not easily repaired. No matter how it is repaired, I'm not sure how much confidence I would have in the end results, as I'd hate to lose it swimming in a lake or river or sea, never to see it again.

Until Garmin change their build materials, I imagine a lot of people will experience this.

So the only answers appear to be:
1. Live with it (clearly not an option for most!)
2. Some sort of resin fix, over the hinge so that the hinge cannot escape through the gap - if you trust it enough!
3. Some sort of strap that the watch fits into - like a silicone cover for the watch with built in strap - does anyone make one?
4. A new case - from a broken Fenix 5 and swap out the innards (Many people won't want to do that themselves)
5. Garmin to step in and offer a repair service (having already shelled out hundreds for what I hoped was a top-of-the-line-watch, I'm reluctant if the costs are high!)

( As for what I shall do with mine, I'm going to try to see if Garmin offer any warranty on my watch. After that I'm going to look at any ways to "repair" it, but also to keep my eyes open for a silicone watch cover that would hold it together if the watch hinge ever gets loose, so I don't lose my watch in a lake or at some other inopportune time. I don't think there are any other options open to me as not willing to buy another watch so soon)

Suggestions to Garmin:

1. Offer a repair service - not a new watch replacement for what could be viewed as a manufacturing fault in choice of material
2. Investigate brittle nature of current material through naturally occurring stress breaks caused by 'extreme' temperature changes or vibration, or other stress inducing action etc.
3. Offer a case (or partner with someone that can cost effectively offer one) that can go over someone's watch and act as an alternative strap when the hinge is unusable, without impeding the heart rate monitor or other sensors.