It wasn't like this until the early version of PS 2022, but it's getting slower and at 23.5, it's really weirdly slow.
I thought there might be a speed difference between turning on and off the option, so I compared it, but the results were the same.
Precise previews for 16bit document on/off
Native canvas on/off
Multithread compositing on/off
Use Graphic Processor on/off
Image Processing- Select Subject(Device , Cloud) : I don't know if this affects object selection, but I tried changing options.
The size of the test image below is really small. 1000px x 667px (sRGB, 8bit document)
The reason why I tested it with a small image was because I thought it was because of the large image and the number of layers.
But if you look at the gif image below, you can see a huge difference in loading and speed
This is Photoshop 23.5's object selection.
Even though the end is cut to meet the gif capacity, the loading time in front is long. Once again, the test image is very small.
And Now this is Photoshop 21.0.3's object selection. you can check this...
PS 21.0.3 object selection
Can you see the difference? It's a big difference.
This is the difference in speed that appears even though the image used in the test is really small. In the actual working image (6000x8000px), there is a loading as if the computer had stopped a little bit. It's the same if you try to select a very small, very simple part of a real image, not a lot of it.
This needs to be improved Speed or delay. In fact, the masking quality of those two images was almost the same.