Wayland is stable. What it's not is stagnant, like X11, which lacks fractional/mixed-DPI scaling, per-window HDR/color management, explicit GPU synchronization, and a security model ready for the modern challenges of the mid 90s.
It's also technically cross-platform, as evidenced by FreeBSD's support for Wayland compositors. But it's not its goal either, the goal is an excellent Linux desktop, not something that serves the 17 people in the world that routinely run the same exact desktop config on Linux and non-Linux PCs.
X11 used to crash all the time, especially after an update, back when it was being vibrantly developed. It's been a lot more stable since it got abandoned. I've not had a crash in 13 years.
Matter of fact, the vast majority has moved on to Wayland years ago, both KDE and Gnome have reported their usage stats and neither sees a point in keeping X11 afloat. I too have been using Wayland (KDE) for years, it addressed some decades-long struggles around multi monitor and DPI layouts. I use input methods for CJK that work better and more consistently than before. As far as I'm concerned, this ship has sailed, for the better.