Cable/charger/battery for Garmin Fenix 6 Pro Solar

Good morning,

I have some questions about cable/charger/battery for Fenix 6 Pro Solar:

1. Can I use any mobile phone charger (for instance, the Samsung ones) for my Fenix 6 Pro Solar? Are fast-charging ones also compatible?

2. I want to  buy a longer cable on Amazon. Is any cable fine even if it's not an original one?

Assuming I can find it, can I also use a cable USB-C  to Garmin? I have a phone charger with a USB-C port (fast charging one) so a USB-C to Garmin cable would help.

3. My watch should last roughly 14 days with a charge. By solar charging it, how much would I add to the overall duration of the battery?

Many thanks