[MovedGoalPosts]

Have you tried a different ethernet cable between the modem and router. It's always possible that is faulty. I can see you are powering the modem and router off when you swap stuff.

I'd do a factory reset to the router to get it back to default settings. Get connections sorted out wired between internet <> router <> computer first, then worry about wireless. It really shouldn't be necessary to clone your computer's mac into the router.