Created attachment 165632 [details]
The crash log, after I installed debug symbols. Crash Handler says it's 3 stars (useful)

STEPS TO REPRODUCE
1. Open Dolphin
2. Resize it smaller until it switches to the compact view (everything should still work fine)
3. Resize it bigger so that it tries to switch back to the expanded view

OBSERVED RESULT
At the point when Discover would switch to expanded view, it stops responding, does not resize or redraw the window, and then crashes entirely and closes. From when Dolphin freezes to when it closes, there is high disk usage.

EXPECTED RESULT
Discover shows the expanded view

SOFTWARE/OS VERSIONS
KDE Neon Testing
Wayland
Discover (according to apt): `plasma-discover/jammy,now 5.91.90+p22.04+vstable+git20240206.0038-0 amd64`
Discover (according to Discover→About): 6.0.0
KDE Plasma Version: 6.0.0
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.1

ADDITIONAL INFORMATION
I don't know if this is related, but if you resize the Discover window smaller by forcing it against a screen side with the mouse / Meta+Left / Meta+Right, so that Discover takes up half the screen, the edge of Discover touching the screen side (left or right) will stop showing the outmost window decoration. In Breeze Dark theme this is a 1px pale grey bar. It disappears, and the standard darker grey window fills the space instead