It's working as it always has been for me, since the early days of 4. It's pretty much dead for me now.
For the record, this has been happening on many machines, and I don't use nvigia GPUs and similar stuff.
Also, I try to report bugs in software that I use, but KDE has the appearance of software which receives no QA at all. It's one thing to report a bug in sway or some XFCE application which crashes maybe once in a few years, and other to use something which crashes a dozen times a day. I'd be filling bugs all day long.
Good software needs a really easy way to report bugs and get back to work. And people to triage the reports. I do not work for KDE, but the bug reporting process treats me like I do.
This has been my experience since KDE 4 too pretty much 4 out of 5 attempts i made to check out KDE, including trying KDE Neon (which included weird visual glitches that i never saw before in any desktop environment).
Though FWIW my latest attempt is openSUSE Tumbleweed running on my GPD Win 1 (which isn't exactly a mainstream device, though it does have an Intel integrated GPU which has open source drivers, which helps a bit) and it seems to work fine there. I do very light use of it however, mainly launching games and such - normally i'd be using Window Maker, but GPD Win 1 needed a very recent kernel to boot and also RandR to be configured to rotate the screen (the 'native' screen is actually in portrait mode but the computer uses it in landscape) and i didn't want to bother with that at the moment i installed it so i grabbed the first non-Gnome-based rolling distribution that had official support for some form of desktop environment that i expected to have a GUI application to setup rotation... which basically meant KDE :-P.
What distro? New or installed on top of something else?
I have run KDE Neon since a few years ago om two (admittedly high end) laptops and it has been very smooth.
I have been using always-latest KDE5 with Manjaro on a very old (Core 2 Duo, Intel graphics) laptop for some years already and it's perfect. Less than 5 crashes a year.
KDE4 would crash as soon as I attached an extra display. KDE5 also crashed often when it was immature. Now it works like a breeze. As somebody who has watched (and tried regularly) KDE since the inception of KDE3, I can say KDE has finally reached maturity (if not perfection) about 1.5 years ago.
But the two main reasons i think KDE 5 is worse than KDE 3 is that as a UI it follows the same pattern as Gnome 3 (and Windows 10's "modern" apps, sadly) for wasting screen space everywhere and it does feel like it has a lot of moving parts everywhere which aren't exactly fitting perfectly with each other even though they are made for each other (i know that KDE 3 was probably also similar, but it always felt solid and stable - i wonder if breaking kdelibs or whatever it was called to a myriad of tiny little libraries that all applications and each other needing to be there anyway made things more brittle, though that might be my bias from whenever i try to install a KDE application in a non-KDE environment and i get a dependency vomit from the package installer).
I might sound too hard on KDE 5, but TBH if i absolutely had to choose between it and Gnome and had no other option (or the other option was a tiling WM - which i never liked), then i'd use KDE. It isn't bad, i'd still install it on a computer i do not want to fiddle around with much.
I have fond memories of KDE 2/3 and GNOME 2. I also ran KDE 1 and GNOME 1 back in the days (initially GNOME cause of RedHat Linux and the license issues with KDE). If you compare them to Windows 9x and early NT they were quite good.
For example I do not think to this day there is anything tech-wise like COM with all of its related tech like OLE (which allows documents to embed objects exposed by other applications which themselves can run in 'embedded mode' to edit said embedded objects), ActiveX (which in a similar way allows applications to make use of reusable controls that can describe themselves), Automation (which allows applications to expose scriptable interfaces that can be called by any other application), Active Scripting (which allows applications to embed scripting languages which themselves are registered with the system so that, e.g., you can install a scripting engine for Python which then can be used to script any application that uses Active Scripting even if that application has no idea about Python) and a bunch of other things.
(note that DBus does provide the 'expose interfaces' part, but it is only about that whereas COM is a more generic technology that was used for all of the above)
[0] https://techbase.kde.org/Development/Tutorials/Using_KParts
ActiveX is just a standardized way to embed controls, in practice it isn't any difference than any desktop application that has support for plugins nor any less (or more) safer than that. COM in general is just a standardized form of a plugin system with a bunch of predefined interfaces (or binary protocols if you want) for applications that weren't written with each other in mind to still be able to work together and share functionality.
It seems somewhere around the late 2000s both projects got very nice and usable desktop environments, couldn't figure out how to "evolve" next (because apparently software just can't not evolve) and started throwing shit at the wall to see what sticks. And unsurprisingly, a lot of it did stick.
To its credit, KDE 5 does seem to try to clean up the mess a bit though in that over the years it is the only between the two that doesn't compulsively make me want to remove it from any Linux machine i get my hands on (and can remove stuff :-P).
Sadly XFCE seems to be heading down the same way.