XPS 15 was not designed for gaming and for now, Dell or any other OEM has no intention of making "the perfect" performance + portability laptop, because Profits. Deal with it. If you want to game, get a gaming laptop.
Second, matt anti-glare screen protectors are available for glossy screens. They're not all high quality though, so try out a few ones and be wary of cheap ripoffs that scratch easy.
Lastly, I can also vouch for Lenovo Ideapad 720s 15 with 1050 Ti and not just for its performance, which is only ~5% off a non Max-Q variant. Cooling is excellent as the chassis can easily handle overclocking with MSI Afterburner, unlike the Zenbook Pro UX550UE which still throttled heavily after mods.
But what really impressed me was the hardware. Build quality is on par with XPS / Spectre and much better than Zenbook / Aero. I actually prefer 720s' keyboard and touchpad to the XPS 9560. FHD screen on 720s is equal to XPS in terms of colors, contrast and brightness, although if I had to guess the 4K UHD screen on Dell is probably better than Lenovo's. Battery is 79 Wh and lasts around 7.5 hours which is a bit less than XPS's 9 hours but bearable since there's a second M.2-2280 NVMe storage slot. Also not that it really matters but TB3 port is PCIe x4 unlike x2 on the XPS.
What really sold me though was the price compared to the XPS or anything else. My config is a $1,200 base i7 model with 8GB of RAM and 256GB SSD but with Lenovo's discount I got it for $900. Now returned XPS 15 9560 cost me $1,600 with the discount and for worse dGPU and storage.
So unless you want its 4K touchscreen, stick with Lenovo. But if you want the best quality screens and money isn't an issue, SB2 13/15 or MBP 15 are far better options than XPS.