Graphics cards and gaming consoles are heavily affected by availability of many other things than their headline processors. There's a ton of other parts in there, power management ICs, level shifters, muxes, switches, all sorts of tiny cheap parts that are out of stock. Suppose you're making a game console. You're missing one power management chip, and suddenly you can't produce any units unless you redesign your board for another part, assuming you can get it. It's enough for a single part in your bill of materials to be out of stock and you can't manufacture anything. This dependency means you will tend to buy as much as you can of all the parts you might need, draining the market of any excess capacity. Apple needs lots of chips other than their SoC - they have chips for power management, radios, digital microphones, sensors, antenna amplifiers and switches. Even if supply for their SoC is guaranteed for years, they can't build a single device unless they have every single part that device needs.

Automakers caused this. The issue is not just that they fucked up and ruined the market that one time in mid/late-2020. The issue is that that one fuckup destroyed the confidence in the market. So you can no longer rely on stock being there when you need it, meaning you need to buy as much as you will ever be likely to need, because you don't know when you'll be able to buy again. So you buy as much stock as you can afford to, and if you can't afford to you borrow money and buy it anyway. This is a big problem, because the signaling mechanism of the market is broken. Any stock that shows up now will be gone instantly, but the aggregate demand for parts hasn't really moved - people don't need significantly more parts, but they do need to be certain they'll have them when they need them, which is why they buy more than they need now. At some point you have enough stock and don't need to buy again for years. This is why it doesn't make sense for semiconductor manufacturers to build out additional capacity - by the time it's up and running 14-18 months from now, there's no guarantee anyone will be buying parts in anywhere near the volumes that are needed right now. So this demand shock at the moment is temporary and nobody can predict how long it will last, but you need to know demand way out if you're going to set up a fab expansion. This is why the bullshit move that automakers pulled is having so much outsized impact on the entire industry.

To answer your other questions:

All complex devices with large number of parts in them are super vulnerable to one tiny part halting the production of the entire device. This is why complex devices are poorly available. For GPUs and game consoles in particular there's an extra market-distorting factor of bitcoin fuckers and scalpers, respectively. Apple builds complex devices with large numbers of parts in each.

You can't use a 7nm fab to build things you would normally build on 120nm. Not only is there way too little 7nm capacity, and it's much more expensive per chip, but the smaller the node size the higher the defect rate is going to be, and the lower voltages your parts are going to be able to handle. Automotive and power electronics need to handle high voltages. You will never see 7nm process parts being used for switching mains voltages, for example, or driving 600V motors. In addition, designing parts for newer processes is a lot more work and has very long setup times.

None of the chip shortage can be attributed to AMD or Apple or Intel. They are a totally different category of part/process than the ones that are currently most affected. Intel is still operating near their capacity and selling countless server and laptop CPUs. I don't think this is a factor at all here.