Should I upgrade this Legendary Weapon?

So i got my first legendary weapon for Administrator (my main) and apparently the effects are really good. It applies electro on hit and has elemental flux which also turns my skill electro and gives me a 20% electro boost aswell. However the weapon is only Rank 5🥲 And i feel like it will take ages until i get another weapon that has that combo (if i get it again at all). Would it be a waste to upgrade that weapon since its such a low rank?