Your current rig should work fine on the settings you described. There's no actual bottlenecks visible in the DxDiag excerpt. A more complete version of it might reveal potential driver issues and such but if you're using the original Dell installation the drivers shouldn't be the culprit either.
People run AH, both 2 and 3, on much weaker systems without major problems. I know, I'm one of them. My current one still keeps me above 30 most of the time. The only single digit drops have been at certain spots over a crowded field, an issue in the terrain rather than the system.
I suspect there's quite a lot of background activity going on. If they're programs you're deliberately chosen to run, a new rig won't fix that. Then again, if it's something you don't know about, getting rid of background clutter is the first thing on the to-do list. The worst scenario of course is well hidden malware hogging your resources. In any case, that should be fixable.
The video card you're using scores about the same as mine, the rest of your system being superior. For what I've learned from people having similar systems than mine, a GTX 1060 would triplicate my frame rates. If you're planning to get that monster system, replacing the video card only might give you the desired result. Oh, and possibly the power supply, too, depending on your video card choice.
