To answer the second question, what new PC spec - that’s the million dollar question. If you want the no-holds-barred best experience you can get you have to go right to the top of the range. But your ask - 30FPS consistently on High settings (there is no Very High, there is Ultra beyond High) - will still need a pretty beefy PC to achieve.
My $0.02: I would go for a 13th gen Intel CPU, the Core i5 13600K would not be a bad choice but it’s still a 320USD CPU, and the price differential up to the i7 13700K is just another 100USD. Similar (if slightly inflated) prices in my neck of the woods (the UK). I wouldn’t go for an earlier Intel CPU generation because price/performance is just not as good. AMD is a good option also but I don’t really do Ryzen so I can’t advise.
32GB RAM is really the minimum I’d build a PC with these days. I would go for DDR5, but honestly, DDR4 is fine… but you’ll have to pick a motherboard with one or the other kind of slot, none of them have both.
For the GPU, I’d be quite comfortable going for an NVidia 3000 series card, although I wouldn’t go lower than the 3070 and I think the 3080Ti is a good card that’s finally starting to get cheaper (but not much - supply issues with the 4000 series cards mean 3000 series are still overpriced). Some people will say ‘but DLSS 3.0’ which is cool since it can double your FPS, but until there’s AI training data for MSFS in the drivers, the generated frames will be noisy and artefacted. If I were building a PC today I’d still go for the 3000 series.
Disk - NVMe, not SSD and certainly not spinning rust, and as big and as fast as you can afford. MSFS eats storage and it wants to read that data as fast as it can.
Now all of that means a high-end machine, but you would need that to meet your goal IMHO. If you’re willing to be flexible on your goal - lower some settings or your FPS expectation, then you can achieve that with more modest hardware. I tend to think, though, that it’s better to wait until you can invest in a great system than to buy something much more mid-range and then be unhappy with your performance. MSFS is in some ways the new Crysis (as in ‘…but can it run MSFS?’)
And honestly… I’m sure people will be able to chime in here with system specs quite a bit lower than that who get 30FPS most of the time. I just loaned an older i9 9700K + 1080Ti system to a friend and he’s getting 40+FPS outside of the big cities and major PG scenery areas. So take my thoughts with a pinch of salt because I’m well known for over-speccing my hardware
Hope any of that helps…