WHY IS PHOTOSHOP SO SLOW?

To put my opinion carefully, what you feel is like me.
The pace of Photoshop's start has slowed a lot since a certain year, and it is now at a level where it will be felt.

https://community.adobe.com/t5/photoshop-ecosystem-discussions/p-ps-splash-screen-why-am-i-getting-rings-of-power-ad/m-p/13165312

As a case in point, we saw more and more reports of splash screens.

To be honest, I didn't even know that image would appear when Photoshop was running until 2016. This is because when you press the shortcut icon, Photoshop runs almost immediately. (Just as it runs directly on Apple's m1, m2 series now)

Apart from the high-performance SSD (m.2), the Photoshop Startup speed of the Windows OS has slowed down a lot.

To break down the starting point, I think this is this.

Photoshop CS3~CS6 // Photoshop 2014~2015.5 // Photoshop 2017~2019 // Photoshop 2020(21.0.3) // Photoshop~Until Now 2023(24.0) ........

It is a difficult choice to choose the Photoshop version only with the loading speed, but there is a huge difference between the versions that actually feel smooth, instant, and fast while driving Photoshop.
Of course, the more recent Photoshop updates, the faster the export speed. Many Photoshop benchmarks also say this.
However, most people who use Photoshop have a faster or slower experience with real-time feedback while using Photoshop rather than spending time on exporting.

Out of the comments you wrote above,,,, "So your saying my machine which I can use for creating 3d animation, simulations and rendeirng isnt power enouogh for Photoshop?" <<

This is what I think. While using Photoshop, some level of CPU and GPU should be based, but no matter how high-end it was, I couldn't feel much improvement. It's a matter of optimization that depends on the version and it started quite a long time ago..... 
To make a pretty serious comparison, working on a CS6 on an older computer feels much smoother than working with the latest Photoshop on the latest computer with 128GB of RAM.
Starting in 2017, Google and Adobe Forum (including the former Adobe Feedback Forum), Reddit, Facebook, and Twitter communities have also begun to see a lot of posts on topics such as "Why My Photoshop is so slow?" Before that, there were often people who lacked RAM, and it was solved by replenishing it, but now, no matter how much you upgrade your computer, you can't feel the softness you've been using for decades.

The writing got longer. I'm sorry.
What I'm saying is that what you feel is true, and there's a speed difference depending on the version. Don't doubt your computer because it's good.......

I haven't a clue whether your system is powerful enough, just stating what is needed (I use Macs).

Did you reset your preferences?

So your saying my machine which I can use for creating 3d animation, simulations and rendeirng isnt power enouogh for Photoshop?

The latest versions of Photoshop need a powerful recent computer.

Did you try resetting the preferences, which you can do under the General tab (then closing and reopening the application)?

There's Photoshop Elements, which is a kind of Photoshop light.

I miss the old days when Photoshop was a simple pixel program. Maybe we need a simple version of Photoshop for simple tasks without all the memory fluff?

Latest Subscription Photoshop, 128mb of RAM, 5 TB of SSD, Windows 10 updated, RTX 3090 graphics card, 

I use Maxon C4D, After Effects, Photoshop, Media Encoder etc...
Photoshop is a real memory hog, After Effects too

Which (exact) version of Photoshop and OS?

How much RAM and spare hard disk capacity do you have?

Have you tried resetting the Photoshop preferences back to the factory defaults?