1. No, it is not soldered. It's actually very easy to change. All you have to do is remove all the screws from the back (including the one in the very center under the sticker).
2. The SSD is M.2 2280, not M.2 NVMe. 3. It cannot be changed to a 2.5", it has to be in the M.2 form factor. 4. Yes, memory is changeable but one of the already installed memory sticks is soldered to the board. It's much harder to get to the RAM than the storage as the ram is on the opposite side of the motherboard, same as a lot of Asus laptops.