Photoshop 2019 and 2020 laggy and stuttering on Windows 10

I'm running a decent photo editing rig. I got an Intel Core i7 6700 with 32 gigs of RAM, with Win10 Pro v1903 and Photoshop booting from a 480gb SATA SSD (which also works as the primary scratch disk and is not full), and to top it off I have a GTX1060 with 3 gigs of RAM for hardware acceleration. All of this should be quite enough for Photoshop, and I had no problems working with the program on lower specs at work...
Until I bought Photoshop 2019 and 2020 for my home studio...

And my workflow slowed down to a crawl.

Here are a couple of examples.

Working with layers that move relatively fast (for example some backdrop moving horizontally in a simple linear fashion) is an experience that can be best described as stuttering; the movement is uneven. This applies not only to internal playback but also to the end result, exported files (h.264 mp4).

3D objects and video clips experience freezes and lags. When I try to produce a moving image with more than two layers, the initial render is usually very slow - meaning whenever I try to play the timeline (and the colored line over the timeline appears for the first time), the first playback is very slow.

3D in general slowed down to a crawl. Any sophisticated geometry is now impossible to manipulate, best I can manage now is a 3D text sign, with no textures all light sources. When rendering 3D I have to set the render quality to 3, because with quality 4 or 5 the process takes forever - even if we are talking about that simple sign.

Not about animation and 3D: More often than not, taking a sample for clone stamp or healing brush also lags - even if it works correctly, making a show of grabbing a sample promptly and immediately using it (as it should be during common retouch workflow), it actually fails and grabs a sample from where the clone should be going, resulting in wasted time and effort. I have to wait about a second for the program to actually register the sample picking point and only then I can click on a new place to apply it. Adobe Supp has advised me to use Premiere Pro for video and animation )))

Rendering a clipping pass preview in the mask editing window takes forever. Mostly I use the button for masking hair and fur; if I press it to mask an object, preview takes a very long time to build, forcing me to wait three to four seconds - after EACH click of the brush.

Turning on the old compositing engine helps somewhat, but I did not buy it for using old.

In my experience at work, Photoshop was always snappy and responsive. I’ve been using it since professionally since Ps 5.0 (in 1998)))) and there were no problems until CC2019, but now it’s laggy. 
To be honest, the last non-problem version was CS6 🙂 But since CC2019 it's got worse... 
Sometimes, some functions can randomly decide stop working for no reason. If this happens, the only way to fix it is restart.

Bottom line, I have expensive hardware for professional software… so I cannot understand or even begin to fathom why this is happening. As of yet, Adobe support staff has been unable to help me (the case is not even escalated to somebody who knows anything apart from a tech support script)... so, any advice, software, hardware, whatever, would be more than welcome at this point.