New to Fly Away But not to Sim

Hey all,

Not to use this thread as an intro but as it is my first post, I guess it is. 

I have been with MS Flight Sim from 1999 to 2016 so saw it all with the highs and lows of the different flight simulator editions.

I have been away from it for a few years until recently when I stumbled across FS 2020. Obviously it has got the interest back!

Anyway, I now have an iMac (looking to sell on) which is a 2014 iMac 5k with a 3.5 i5, 16GB Ram, 1TB Fusion Drive, and 2GB ATi GPU.

Anyway, I tried Bootcamp to get FSX on and it's horrendous. My last home-built PC between 2012-2016 was an SB i5 2500k @ 4ghz, 8GB Ram (i think) and I can't even remember what GPU (only 1GB though). That PC ran FSX with a lot of ORBX and AI somewhat too bad, so no idea why the iMac is struggling. I have since bought Xplane and whilst better than how FSX runs, still not ideal.

SO

I am looking to build again. My question has no right answer I imagine but would it be naive to go all-in now with something along the lines of the following?
i9 9900
64gB Ram
2080Ti 11gb
2GB m2

Is spending around £2,500 stupid considering FS2020 is still in testing?

Or should the above future proof a scenario as to what FS2020 will throw at it? 

Thank you for anybody's advice.