I don't normally recommend to people that they wait, because there is always something better coming down the pipe and around the corner, but in this case I think if you are going to spend that kind of money it would be a very good idea to wait and for a couple of reasons.
For one, the prices on graphics cards are dropping currently, so waiting a couple of months might result in a substantial savings PLUS the next generation Nvidia cards are supposed to release no later than October, and you're looking at a probable minimum based on early projections of something like 35-45% performance increase on the upper end cards. Obviously, this isn't a "just buy it" moment, so actual reviews would be desirable before making any determinations on that but regardless it is probably a good idea to wait if you can even get 25% more performance for something near the price of existing upper end cards.
And then both AMD and Intel are releasing new CPUs in the not so distant future. AMD is expected to release it's Ryzen 7000 series in September and I'd be very surprised if the Intel Raptor lake models didn't release somewhere in the same-near timeframe or not very long after. Given that both these architectures are expected to bring a 10-12% performance increase over current models and if you don't want to be CPU limited, assuming you go with a relatively higher end graphics card AND especially on a very CPU intensive game like flight simulator, you'll actually have a very strong desire to see that additional 10% in single core performance especially when applied across the six or so cores that it can utilize.
If you MUST have something now, I'd be glad to help you with a build outline, but I seriously think waiting a couple of months for the core hardware is a good idea. Cases, power supplies, memory, SSDs, these are all currently trending downwards in price for the most part so even for those items it might be worth waiting at least a little while.