Devices with cryptic names such as hangzhou device have connected to my router, what am I supposed to do now?

These (Hangzhou devices and others) are not real devices. Your network device has some sort of memory fault and is displaying memory as "addresses". You can see that the device names contain sections of some JavaScript-like code. The IP and MAC addresses, when ASCII-decoded, show similar data:

120.91.105.43 = 'x[i+'

32.97.44.32 = ' a, '

34.99.101.110 = '"cen'

63:20:3d:20:69:69 = 'c = ii'

20:62:3c:74:64:20 = ' b

Not coincidentally, the "BC:3B:" in the last address is the same as the beginning of your first MAC address listed, which @Anti-weakpasswords notes belongs to an Apple device. I would recommend rebooting your device, and checking for any available firmware updates from NETGEAR.