If someone somehow enlarge the 1px handle for windows resizing by default (not default theme) I can say 'it's perfect'.
The workaround for me is to always resize by clicking Alt, right click, and drag. At the end of the day, that's probably just straight up easier, since you never need to bother getting close to the borders of the windows.
That is not XFCE itself, that is up to your theme. I'm on the Dracula theme and have about 16 pixels.