Fenix 7 pro sapphire solar seems bricked

Hi !

I bought a new Garmin Fenix 7 pro sapphire solar on Vinted (second hand website in Europe) 3 months ago. I was very happy with the product until it shut down during a kitesurfing session. I can’t seem to start it again despite trying to press the light button for a minute, using a different charger, plugging it on my computer, …
Support is offering to replace it but as I don’t have the purchase invoice (seller didn’t provide one) they’re asking for ~320€ for the replacement. It’ll end up costing more that a store bought one… I know I am responsible as I bought it second hand, but it still hurts to pay the watch a second time.

So before accepting the offer. I’d like to check if anyone had the same issue, or if you have any other suggestions for me to try.

Thanks in advance