Not sure to what extent budget is driving your component choice, so take this all with a pinch of ‘you’re spending how much on a PC?’ salt.
I would suggest going for a 13th gen CPU if you can. You definitely get improved performance over 12th gen. That said, we’re talking +5-10 FPS, not +50. The 13900K turbos to 5.8GHz out of the box, and some people have overclocked it to 6.2 on one core. I never thought we’d break the 6GHz barrier without significant new technology! 13th gen chips work in Socket 1700 boards with Z690 chipsets (and will probably be the last generation that will), so it’s always an upgrade choice later if you do go with 12th gen now. I just did that upgrade (12900K → 13900K) and while my bank manager hates me, I’m happy with it and now I have a 12th gen CPU available to build a new machine for coding 
I would also suggest going up to 2TB on the NVMe, it’s not super-expensive, and get one that can do PCI Gen 5 if possible. You can’t have enough super-fast storage for flight sim. Hell, I’m considering swapping out for a 4TB drive, but as you can tell already, I just love to spend money…
The 3080Ti will be a great upgrade from the 1080Ti. I did the same thing in 2021. I’m trying to resist spending absurd amounts of money on a 4090 right now. In truth it’s probably only the availability - I’m not buying a Palit card no matter what anyone says - that’s stopping me.
I may have a problem.