Since you are equipped to deal with high temperature metal working, I would recommend taking the following steps.
1. Depopulate
2. Run a ceramic magnet through the material and pick up the nickel containing pieces.
3. Grind what is left into powder with a coffee grinder, use a espresso grinder.
4. Weigh the material and take equal amounts of zinc oxide and aluminum dust and mix it together. (Alternately, you can take the weight in aluminum foil plus the same in zinc oxide powder plus the grind and roll the foil with a strip of magnesium diagonally along the inside of the roll with the powder in the center, aluminum is flammable as foil.)
5. With a strip of magnesium ribbon as a fuse, put the mixture in a crucible and ignite the mixture using the magnesium fuse. Or light the fuse on the roll inside of a crucible, like you would use for iron smelting, not a little one ounce thing.
https://www.sciencedirect.com/science/article/abs/pii/S0272884217320977#:~:text=The above-mentioned values reveal,In fact,
The aluminum will burn off at a temperature in excess of the evaporation point of zinc metal leaving behind aluminum oxide and a blob of metal at the bottom of the crucible that will be predominantly silver, gold, copper and palladium. The rest will be aluminum oxide.
Just sell it as is. Somebody will pay you a lot more money than doing anything more would cost you.
If it is a smartphone, the mainboard PCB will be a gold and silver alloy, not copper, shred tablet, phone and small electronics boards and mix them in with the thermite and burn off the cellulose in the process, but this will make the mix burn hot and smokey.
As for fingers, containing a layer of gold on nickel layered on copper, believe it or not, but you can just sell those on eBay for about what you would expect to get by going through some process to extract the gold at home without chemicals.
Hope this helps, zinc oxide is cheap and aluminum foil is even cheaper and you can spend $20 in materials to extract up to 1 kilo of ewaste alloy.