Congrats on your purchase!

I also have a problems with big screens, so I understand why you find it hard to adjust to a 32" monitor. I'm on a 23" one and think that I could still take a 25" monitor (thankfully there are some 1440p ones in that size), but 27" or larger are a no-go.

I have had a 1440P monitor for a decade or more now. It's always a bit of a shock going to a 1080P or 720P display.
I would overclock that monitor to see how far you can push past 75hz though.

As for the size issue... You will get used to it, you will start to focus your eyes roughly in the center and let your peripheral vision handle the rest, just takes time.
My current display is 32" and I would probably not be against the idea of a 40-42" 4k display.

It's because PC hardware has long outstripped software/game development, so all those extra horses that the PC has? We tend to sink it into resolution and framerates.
1440P has been a "mid-range" resolution for years now, especially once cheap Korean 1440P, 27", IPS panels started to flood the market and companies like AOC gained a foothold.

I disagree :) If you look at Amazon bestsellers, most people buy 1080p monitors today.

I remember how nice it was when I got The Witcher 3 and cranked it up to ultra with 1440p on my new rig and got a good 65-70fps, I actually bought the rig for TW3 specifically, wanting to max it. My joy ended when I tried to use Nvidia Hairworks though, it cut my fps in half on its own, no nice beard and hair in the world is worth that!

Only makes sense that low-end, cheaper stuff sells more in volume than something that costs more in the mid-range.

It's not just the display resolution that is mid-range, it's also the hardware necessary to drive it... A Radeon RX 580/590/Geforce 1060Ti 6GB/1660 is mid range hardware that is actually good for 1440P.

You can run games on lower resolutions on a 1440p monitor. My PC is aging too but surprisingly my Geforce 960 2GB handles modern games at 1440p well. I'm playing DMC5 on High now and framerate is smooth. I had gotten a used AMD 580 earlier this year but it turned out mined with loud fans and I sold it off.

Any mid-range GPU is fine for 1440P (Radeon RX 580/Geforce 1060 6GB or better), it's not a difficult resolution to run these days.

Do it and don't look back.

Usually you will stick with a monitor for longer than a PC, I highly doubt you are going to continue with that same GPU for the next half decade?
A GTX 960 will handle most games (even newer ones) at 1440P with some detail settings turned down at 30fps.
If you want 60fps, even at 1080P you will have to turn details down.

https://www.anandtech.com/bench/product/2302

You should look at around a 22-50% performance impact by moving from 1080P to 1440P with ultra/very high details, but that is likely the limited framebuffer coming into play. - The jump from 1080P to 1440P is a 77.7% increase in pixels afterall, so it's good bang-for-buck.

Older games will be no issue.

Outside of gaming, you will have crisper text and images, you can throw more information on your screen... And you will even see some benefits with 4k video over 1080P video.

I joined the 144hz race, 1080p gaming laptop came with 144hz screen. Not that it can run modern games at 144hz, yet 72 fps is nice.

Iv been gaming on my PC at 4k/60hz on my 55inch TV.. i was thinking of buying a monitor but not sure if going from 4k to 1440p is going to be a noticable difference in a downgrade.
I heard 1440p is a very good resolution from 1080p to 1440p.. but what if you are use to 4k going down to 1440p?

The jump is like going from 720P to 1080P... Which is because 2560x1440 (1440P) is 4x the resolution of 720P and 3840x2160 (4k) is 4x the resolution of 1080P,  so it's the exact same relative jump.

But whether you will notice a step down from 4k? Well. That depends on panel size, viewing distance, eye quality and so on.
On a 27" display, the difference between 1440P and 4k is probably not going to be as pronounced as a 55" TV that's for sure, all about the perceived pixels per inch though.