You need to quantify horrible. Are you using a high TLOD? Have you tried dropping it to 100 say? Are you using AI add ons if so which and what density settings? I think given locations of certain airports next to dense city photogrammetry scenery it’s inevitablly going to see fps drops.
I was using KLGA freeware for example with my TLOD at 100, and saw reasonable framerates while departing, but dropped to single digit slideshow on arrival. Now that is a sim issue I think not an airport issue.
I also recently found I had some bugged AI models killing my framerate too. So it can be multiple things rather than just the airport itself.
I’ve found KEWR to be fine (as well as Ini’s KLAX and EGLL(V3)), but with my TLOD tweaked down a bit, and AI traffic dialed back a bit.
Also be aware that fps dips and stutters are usually cpu limitation situation, so do all the other things to drop cpu utisation like moving sliders for other traffic (airport vehicle, workers, vehicles, roads, ships down to say 10) they are CPU loaders. It all still looks ok without them being dialed up to 100 (default).
If you are GPU limited try with DLSS enabled.
Until the devs find ways of better cpu core utilisation, it’s always going to be about tradeoffs with this sim.