It shouldn't cost you anything to get the battery replaced because the 2019 is covered by the battery warranty extension. If for some reason you don't qualify, then don't buy it at the dealer. Go to your local auto store and buy a good battery (the OEM ones are junk).

As for the portable jump pack, never heard of that one you linked. I have a Noco brand one I carry around. It's very highly regarded (I watched and read way too many reviews before deciding) and cheaper than the one you linked to as well.

This is the one I have: https://www.amazon.com/NOCO-GBX45-UltraSafe-Powerbank-6-5-Liter/dp/B0924V8SPC