I disagree with this (not platformer = not metroidvania) point of view.
The main core of Metroidvanias are the focus on progression through power-ups, exploration (both of these are the factors responsible on the backtracking in the genre) and atmosphere. That doesn’t mean there is a need for jumping (most metroidvanias do as a platformer mainly because the genre was popularized with that kind of view). There is no better example to this point of view than Metroid Prime (mainly the first one). Even tough it’s not a platfomer (but rather an FPS), it still is a Metroidvania because it has those points as their focus.
So if your game has those points as the pillars for the gameplay, you can do whatever style of controls as you want and it will be a metroidvania.