There is nothing to be confused about.
Those outputs can help if they show anything that can actually help; the commands don’t magically return “OK, here’s the problem”; sometimes outputs may be a good indicator, at best. Without these (and likely more) outputs, it may be difficult for anyone to help at all, which is why I (and others) will usually request them.
Your inxi output shows you have no swap space defined - that can potentially be problematic - however, it has nothing to do with the issue you describe:
Your journal output shows many failures consistent with your system being broken, resulting from an interrupted update, but it’s difficult to see exactly what. It also shows that you didn’t use the expected update command (it should be sudo pacman -Syu).
From your /var/log/pacman.log it looks like your crash happened here:
Whether it’s recoverable (or not) in it’s current state, I can’t say; maybe others have some insight; you’ll need to be patient.
You told us:
However, you didn’t tell us whether the update completed; or, if it didn’t, what the output from the attempt was.
You still haven’t responded to:
Do you actually have both XFCE and Plasma installed in the same OS?
Any information might potentially be useful.
In the meantime, you could be helping yourself by searching the forums; here are a few links that might be useful;