Your PC is already more powerful than mine… Lol… 
I don’t think you’re going to have a problem with running the sim. Heck, I run mine on 4K HDR with ULTRA settings on a weaker PC than yours and it runs fine for me.
If I may ask, why do you need a lot of detached displays? Are you building a home-cockpit setup?
Either way, I guess you need to do a bit of benchmarking process and troubleshooting, use the DevMode FPS display to determine where you’re getting your bottleneck from.
If it is a Limited by MainThread, I also had a similar issue, which goes away after I followed this post. Otherwise, you should be fine running the sim on Ultra with that spec. But if there are still few things that drops your FPS, you can reduce some graphics settings.
Just note, you don’t need to aim for 60 FPS, flightsim on 30 FPS is more than good enough. So just keep that in mind on how to target your settings.