The thing with monitors, people fail to realize is that it is the single most important piece in the chain for graphical fidelity. After all it is the last step where all the work your computer does making an image comes to life. Now I'm not gonna lie to your face that the rest is unimportant, you still need a good GPU to draw a good image in newer games. But the point is that the even best examples of the latest and greatest VFX will look like ass on a bad monitor but on a good monitor you can see what VFX new and old have to offer in their best light. Now that's not to say that a lower res is automatically "bad" but rather to elevate the importance of the monitor in your setup. Don't think of it as an afterthought "oh I'm building a PC with these specs, I should get x monitor" make your build around the image you want. How large do you want the image, how sharp, how fast, is color accuracy important, is color vibrancy important, is HDR important, etc... pick a monitor that meets your demands, then pick a GPU that can fulfill those demands in the games you play and plan to play. A good monitor will usually outlast several builds, so it's a worthwhile investment to get a good one.

Personally I value a moderate size sharp image with very accurate colors in a variety of color spaces, and I want it to be capable of fast frame rates for multiplayer games, with variable refresh. I also want to be able to drive this display using a midrange build with infrequent upgrades. That eventually led me to QD-OLED at 27" 1440p 240hz. Now I would've loved to have 32" 4k 240hz, but that last bit stops me, I don't want to run a super expensive tower that puts out a lot of heat. 1440p for me strikes a good balance of large sharp image, with moderate hardware requirements. when I built my system I was always planning to play 1440p with at least 60fps on single player games, and 100+fps on multiplayer, so at the time I got a 6700xt (mostly because it was impossible to find 6800(xt) local). it's served well and still fulfills my goals in the games I play.

Talking specifically about resolution difference, on my desktop I cannot go back to my previous 21" 1080p, it's just not big enough for my gaming taste in that setting. when I switched to 27" 1440p I wouldn't say I was "astonished" or it "changed my life", but the extra size was a definite boost in immersion. Beyond the initial "wow it's bigger", it wasn't something I noticed daily, the extra screen space for non games is extremely valuable, probably the most "noticeable" improvement. But in games the extra immersion from a larger display taking up more of your IRL FOV is a "silent gamechanger" at least for me. It's not a "wow I'm so much more immersed" it's just, being more immersed, less distracted, ~~really makes you~~ ~~feel~~ ~~like batman.~~ Of course this is all subjective and you might find that it's a complete waste for you. Kinda like how some people don't care for movie theaters because a huge IMAX screen with crazy high end sound system subjectively changes nothing about the movie watching experience to them compared to their 55" TCL with soundbar.