Display Enlightment by NCX

I'm starting to suffer from <120 FPS in games and it's invalidating my monitor's usefulness.

It's possible to save a few FPS by using a custom resolution of 1440x900 (more FPS; small black bars on all sides) or 1680x1050 (small black bars on the top and bottom) with Nvidia Aspect ratio scaling or a displays 1:1 pixel mapping.

New Build:
i7 9700k // 1080 ti or 2080 ti // 16 GB 3200ish? //

2080 ti of course.  The 2080 ti is perfect for 144-165fps @1440p and good for 4K-60.

I have about a 2' - 3' viewing distance to work with for the monitor.

2.5ft for an ultra-wide 34" IPS, and more if it's an UW VA panel.

Are gamers still trending towards the higher frequency/hz feature, or have we started to trend towards visual fidelity/quality?

I prioritize image quality, but not to the point where I'd recommend a 60hz AHVA/IPS/PLS panel to someone asking about budget (<300$) 144hz monitors.   

Can you suggest a few monitors, I should definitely be considering, with the information I have provided?

Budget?  The only affordable monitor for PC gaming with Nvidia cards I like are the matte AOC AG271QG (review links) and the discontinued Viewsonic XG2703-GS with 144-165hz 1440p AHVA panels (marketed as IPS) with G-Sync.  Both are better than the Acer XB271HU (worst of the 4), cheaper (100$+) than the Asus PG279Q (most common back-light bleed, though the unit I tested was bleed-less)  The Asus is theoretically more accurate (the unit Rtings tested a few months ago was significantly more accurate than the unit I tested in 2016) than the AOC, but it lacks gamma settings to combat the low preset gamma these monitors can come with while the AOC and Viewsonic have gamma settings.  All four of the monitors I tested came with low preset gamma (Viewsonic was the best but still needed a gamma increase), but the AOC and Viewsonic have the most accurate color presets.

G-Sync is amazing if one hates screen tearing and ustable frame-rates, though some games feel unstable even with it enabled.  I hate screen tearing, but not enough to deal with a matte screen which is why I still use an overclock-able (96hz) 2560x1440 X-Star DP2710 glossy PLS from 2013, plus most of my gaming time has been dedicated to Destiny and D2 (Pro) on PS4 since 2015.  None of the PC games I've played this year (30 hours of Fallout New Vegas until it crashed infinitely, 40 hours of S.TA.L.K.E.R. Clear Sky and 30 hours of Vermintide 1 & 2) suffered from lots of tearing which makes not having G-Sync a worthy trade off for the glossy coating, plus Nvidia Fast Sync (enable in NVCP) works well with some games.  Last fall I played a bunch of Assassin's Creed 3 on the Acer XB321HK (4K AHVA with G-Sync); AC3 is unplayable without G-Sync at 4K with my 980 ti due to tearing and frame-rate instability.  My point is that G-Sync appreciation may vary greatly depending on ones display preferences, and the games being played.
 

what's your quick thoughts on ultra-wides and/or concave screens?

I've been using at least two monitors side-by-side since 2010, dislike matte monitors and both curved and fake bezel/frame-less panels (all UW IPS), plus I already owned 3 monitors I really liked when UW's first showed up.

I noticed on reddit a thread about the future of G-Sync with HDMI 2.1.  Thoughts?

There's nothing concrete in there to think about.