It seems that NanoPi K1 Plus is using rtl8189 WiFi ... Right ?
Driver is broken in 5.11, I'm working on it with other guys, I'm using OPiPC+/OPiLite/OPiPlus2E.
In the mean time, if you don't need WiFi, disable the module :
mv /lib/modules/5.11.1-sunxi/kernel/drivers/net/wireless/rtl8189fs/8189fs.ko /lib/modules/5.11.1-sunxi/kernel/drivers/net/wireless/rtl8189fs/8189fs.ko-disabled