Hey, I faced this dilemma back in November myself. After weeks of researching just about every aspect of a monitor, I settled on the LG 27GN950-B. If I were you what I would do is first make a list of the requirements you would like. So 4k, at least 120Hz and IPS is a good start. Add to that the size range you'll accept, the price, G-Sync/FreeSync, colour gamut and the Grey to Grey time. Once you have your wish list, to save yourself the time of going website to website of all the manufacturers checking all the specs, you can use the most restrictive requirement to create a short list. In this case that would be the G-Sync/FreeSync requirement. G-Sync is a feature of a monitor that enables the monitor to match its frequncy (Hz) to your game's framerate (fps). This is great cause it means you no longer need to use the in game V-Sync option to stop screen tearing. (Which means your fps doesn't have to be limited anymore, it can be whatever the graphics card is capable of putting out and the screen will match it). You have said that you have a 3080 (Same as me!) so you want a monitor that NVidia have certified as at least G-Sync compatible. You can research this further yourself if you like but those are the basics. Suffice to say that you want a monitor that either has G-Sync/G-Sync ultimate or is G-Sync compatible.
Nvidia lists every monitor in the world that they have certified as being G-Sync compatible on their website here:
https://www.nvidia.com/en-us/geforce...onitors/specs/. So your future monitor should be on that list. Now go down the list one by one checking each one against your other requirements. And every time that there's a monitor that matches everything you want write it down. Once you have a short list simply choose your favourite.
Personally, my requirements were 4k, 120Hz, IPS, G-Sync compatible and no bigger than 27". For me the only 2 choices pretty much were an ASUS one that was older and a lot more expensive or the LG 27GN950-B which I bought and can recommend. If you do end up buying this monitor, the only flaws with it that I found were that it doesn't have an HDMI 2.1 which means that although you can do 4k 144Hz on PC you're limited to something like 4K 60fps which is unfortunate if you have a new console. The second minor flaw is that I don't really like the stand. It's made of plastic and doesn't look very good to me. But if you use a mounting arm anyway on your desk then you won't be using it anyway so no worries. Hope all this helps.