Switch != Router, and I wouldn’t use a Zyxel anything even if you paid me - their approach to security is to just not bother, and their hardware is made out of whatever scraps they can find on the factory floor
I used a zyxel mini wifi router once. It would soft-brick when changing the subnet range. There was another cool feature that would effectively prevent a new admin password from taking effect until you entered a second one (basically creating a queue of passwords). That was fun to figure out.
Yeah, I had fun trying to work out why DHCP was totally broken - turns out the Zyxel router would respond to any ARP request it saw, for any MAC anywhere. There was a setting you could enable to make it work properly, but it went in the bin shortly after when I found out the VPN component would let in anyone who asked politely, and that there were ways to get at the admin panel from the WAN even when you had turned that off