1) Dell 24 P2419h
2) ViewSonic Vp2468

A comparative of both:
https://www.displayspecifications.com/en/comparison/9c7b99b05

I usually don't play high FPS games like shooters or competitive, so I'm prioritizing image quality.

1) Best color: Seems ViewSonic have slightly better color?
2) Connections: Dell also have VGA (which is useful in some cases).

They are too similar to me, could you point any difference you think would be more relevant?

Also I accept suggestions of any 24" to 27" / 1K to 4K, IPS technology to run with a GTX1080.

Edit: must to be not-curve.

I can’t help you decide unfortunately, and it’s really up to you anyways as people’s opinions will differ greatly. What I would suggest is if you have a nvidia card, consider a gsync monitor to pair with it. I have a 1080 and a:
https://www.scan.co.uk/products/34-acer-predator-x34p-ips-curved-g-sync-monitor-3440x1440-4ms-100m1-displaypost-hdmi-speakers?gclid=EAIaIQobChMI9oXm8Ni15QIVQ7TtCh3KqgWdEAQYASABEgJEUfD_BwE

It’s expensive, but really pleased with it. Extra room around viewing area, syncs with graphics card, and is 3 times more resolution than hd. For instance, I played ac odyssey on PS4 recently and am just going through origins, the graphical difference is huge, not just the higher range, but the quality of the image.

If someone held a gun to my head and told me I had to buy a new monitor or else, I'd currently go with: https://www.asus.com/us/ROG-Republic-Of-Gamers/ROG_SWIFT_PG278Q/

I'm also packing a GTX1080, but I'm quite happy with what I have at the moment, which is an Asus VG245H.

Thanks, just forgot to say that must to be not curved. I usually see movies from a longer distance reclined in my gaming chair so curved can be a trouble. Thanks, but I need IPS for the colors.

But about these monitors, which would be better?

I don't know about the Viewsonic but the Dell is great quality monitor. Almost happen to buy one a few months ago but got a great deal on a comparable Philips (1/3 the price of the Dell, just couldn't pass and bought two).
Don't know wich is better and probably you can do your work in both of them without much problem. I tend to favour Dell's monitors since only had good experience with them. On paper they seem similar, the major number difference I can see is the slower response time on the Viewsonic but this means nothing because manufacturers do measure diferently.
Checked a few reviews but nothing major (or unexpected) for this type of panel...

One monitor that really catch my eye is the AOC Q3279VWFD8, is 32" though but very cheap and nice quality as well. The high resolution and Freesync makes it one of the best 200€ monitor (IMHO) I can find in my area. Note that there is a very similar model that is VA panel, not IPS.

I'm currently building one pc that will use the AOC 24G2U IPS, if eventually you want (or anyone) a semi decent monitor with high refresh rate. I still don't have the monitor with me and will take a week before I'm able to get it. Most "Freesync" monitors will work fine on Nvidia cards 10 series and up, even if they are not "GSync". Only on dysplayport and newer drivers though.

I can't help you decide either. For various reasons..

Though I'm quite fond of my new ASUS VG278Q.
Except for it's base. It's square, and therefor jutting out over my desk. Since I use it as a secondary screen.
My main screen is a SyncMaster 957MB, and I prefer those kinds of screens, rare as they are.

I will advice you to never buy a Philips 247ELPH. It died on me waaay too quickly.
3 year lifespan, as opposed to my main screens 23.
Planned obsolesce.

Some monitors with built in weaknesses are easily fixed if you know your electronics. You need to change the too weak parts with components of suitable capacity.