Most of the issues and slow adoption were because the core protocol was deliberately kept extremely minimal, and agreeing on all the needed extensions took a long time. Don't take it from me, but rather from KDE developer Nate Graham: https://pointieststick.com/2023/09/17/so-lets-talk-about-thi...
As such, anyone who tried it early probably had to deal with a pretty large amount of non-working stuff, but by now the platform is capable of most features people require and the biggest remaining bottleneck is that software needs to use these new APIs.