I was seeing sort of similar behavior, also Arch 6.5.? x64 kernel Ave Plasma desktop, but on 11th Gen i5. Except my case it wouldn’t pop up 0%, it was a random number around 9%, so it didn’t force a shutdown. By the time I could try to troubleshoot, the battery reading was back to my charge target number. Haven’t seen it do it since my last kernel update a few days ago, but I’ll keep an eye out. I suspect a KDE/Plasma bug…
Using third party USB-PD 2.0 100W chargers and e-marked 5A cables, if it matters.