John, here's a suggestion for an iFly workaround that might help you until spoken traffic alerts show up:
I've found that iFly's Traffic instrument does a fair job of alerting me to ADSB traffic. I have it set to pop up as big as it gets--a hard, black square that occupies at least half the screen. Here it is on my iPhone. (As I recall, on the 740 it's slightly smaller, but I can't check just now.)
It's big enough and sudden enough to catch my eye if I happen to be looking outside in that general direction. (Usually.)
The black square can be located anywhere you want it on the screen and will cover other instruments and buttons to make it even more noticeable.
The big black popup is usually accompanied by a BONG noise if the Alerts are set right. I don't hear it in flight, myself; but piped into the headset or intercom it would probabaly get me to look at the screen even if I didn't notice the big black square.
iFly's minimum-distance alert threshold is 2500 ft vertically and 2 nm horizontally. That's not too different from what you quoted for ForeFlight. (You can SEE traffic much farther away if you want to.)
It's true that in iFly (now) we have to look at the screen to see which direction to look outside for traffic. But we don't have to constantly stare at the screen in order to be aware of nearby traffic. Also, the Traffic instrument is pretty intuitive to grasp quickly, especially for the horizontal plane. The vertical location is given, too, but you do have to do a bit of mental arithmetic.
However, if you have the EFIS open also, traffic is displayed there in 3D, so you see at a glance what's ahead of you and how high or low it is in respect to you. (My only wish there is for the traffic colors to be brighter.) I don't have a great photo to illustrate that--just this screen from a Windows laptop:
My "ownship" is pointed the wrong direction in the Map view because the computer was sitting on my desk, but the GPS wander direction happened to be toward the ESE, so the EFIS depicts N404DP right about where it would be if I had been flying toward it. (You can see my projected track line on the Map.)
There's no black Traffic square in that picture because the traffic was 10300 ft higher than my desk, and therefore no alert was required. But if N404DP had been down at, say 500 feet, it would have been open (in the center of the screen, is where it's set).
So you might give the Traffic instrument a try--if you haven't already--and see if it will make you less uncomfortable about midairs.