YES , i can totally feel and understand your pain.
I'm just back from work where I, again in vain, tried to get the CC20 at least semistable to work. Our machines are even on a higher level then yours , but ...no way to get any windowsversion to playback stable without stutters a.s.o. (interesting fact: the OSX-version runs really good now ...just sitting in front of one)
Using JKL causes reproducable freezing videooverlays or super jerky playback.
And you forgot to mention the most hated issue
...the subscription model ...
that , in combination with this totally broken software since 2 years now (since 12.1) , and the behaviour of this only profit driven company was clearly too much for us.
And here is the good part .
We / I am in a way more covenient position right now. We quitted / I Left ! (my current investigations are only for technical reasons)
We changed everything , and every plan to another product. We are independend from subscriptions and whimsies of salespeople , independent from the pressure to have only one dictated version to run however bad this software is.
We are not bond-slaves of adobe anymore.....
Maybe we have changed to that "other software" you mentioned.
Ask most of the pro-editors and companies who already made that move....what do they recommend.....maybe they can convince you where are the benefits or cons......... (as you said....we are definitely not alone)
I don't hate anything here anymore, because I already left .....maybe it makes you happy as well.
That is the only democracy we still have ... vote with your feet !