Moderator-80-
You’re correct, but there’s probably an easier way.
All routers that I know of allow the wireless signal to be turned off via the setup screen, so you won’t have to potchke with disconnecting and reconnecting the cables.
(What you’re calling “lan” is a network cable.)
BTW, I don’t always get to post responses quickly, but I’ll usually try to do so within a day or two.
Occasionally I may miss something, but it’s OK for you to email me if you’d like to bring something I can be helpful with to my attention (no guarantees I’ll know the answer, obviously).