You might want to check your other thread. After seeing the dell s2719dgf and s2716dgr in person side by side i'd say the freesync version is better and cheaper overall.
I'm in the same boat as you. I have been thinking about getting a 1440p monitor for the longest time now and moving away from 1080p. As for IPS. I do have some experience with the Nixeus EDG 27. It's about as good as its gets and Nixeus is supposed to be coming out with a updated version very soon. You also have the acer you mentioned. But it doesn't come with a adjustable stand however you could always get one since it does have the option. Acer does have a similar model with a adjustable stand called the XV272UP. I've been looking into this monitor myself. It should be similar to the Gigabyte gaming monitor and is $100 cheaper. $500 vs $600 USD. Both these monitors should use the newer innolux panel. The acer you mentioned might have the innolux panel. If it does i'd expect very good colors but a slower panel overall vs the 2015 AUO IPS/AHVA panels. TN panels are the fastest. But the freesync model is a little iffy at 60hz. I was playing Assassin's Creed maxed out on a rtx 2070 and was only getting 60fps ish. At that point the gsync seemed smoother and less blur. But one thing I forgot to mention in the other thread is that you have to set the overdrive to the fastest setting at 60hz on the freesync model. It helps but at 144hz you wanna use either normal or faster or whatever its called. Don't use the fastest setting at 144hz but it can help at 60hz/60fps.