A 2018 RV shouldn’t have “fuses” for the 120V loads. But I am assuming by “checked the panel” you mean you checked all the circuit breakers to ensure they weren’t tripped. If not, that’s the first place to start. After that, you need to ensure the incoming feed(s) (both if it’s a 50 amp) have power, and both sides of all the circuit breakers have power. If any of that is not the issue, then somewhere you likely got critters chewing wires or other similar issues (chaffing, pinched, bent and broken, etc).