I doubt that a sleazy airbnb host would be sophisticated enough to place a decoy router, and if they were, there's probably nothing I could do to stop them.

My threat model would be the host trying to blackmail me and/or get their kicks from watching me.

A corporate or national actor isn't part of this model, because: - I'm a low-priority target - Prevent highly sophisticated attacks borders on impossible/maddening - The likelihood of the creep is probably 10,000x more

I'm not sure unplugging the router would help, but I probably wouldn't find it very inconvenient either (depending on location).

Overall it's probably worth a quick try to locate and unplug it - if you can't find it, hedge your bets and try some other opsec techniques. Just my own approach.