This doesn’t make sense. If anything then the updated Qt 6.9.2 libs from
led to rebuilding Plasma 6.4.4. I mean rebuilding was done on unstable but since you were on testing your 6.4.4 wasn’t rebuilt against 6.9.2. That’s all i can imagine. So yes switching back to unstable and syncing should fix it. Moreover, the new 6.4.5 is released in three days and surely almost directly in Arch hence in the unstable branch.