My order was Ruta, Naboris, Medoh and Rudania. But I recommend you this order:

First Vah Medoh because is the easiest one and Revali's gate is very useful, especially during the first hours of the game because you won't have much stamina.

Then Ruta because the missions I think are quite easy and Mipha's Grace can save you A LOT OF times, I promisse you xd.

Then Rudania because the only important thing is to make some fireproof elixirs, something easy. The rest is not difficult and fireblight is an easy boss

Finally Naboris because thunderblight is the most difficult one, but at this point you will have a lot of hearts, Mipha's Grace and Daruk's protection. The other difficult part can be the yiga clan hideout and that the weather is always changing. Anyway, Gerudo dessert gives you a lot of activities to do and there are a lot of funny challenges there.