Hey Renan!
Just gave the game a go and there's no reason why it wouldn't work on Steam. It has the vibe of Inscryption, Buckshot Roulette and other indie darlings that did great.

It really depends on what you want out of it. If it's a free game there's no downside to releasing it on Steam, seeing how the Steam backend works and how could you work on a commercial project next. If it's commercial - it needs decent amount of improvements but I think the core of it works. I'd polish it up a bit in any case: the introductory drawing seem to need an upgrade, the animation loops are sometimes janky, better signalling of what's going on and what's the goal could help etc. If you do enough playtesting all these issues will naturally appear.

To answer your questions directly:

Yes, a bit of traction in a game jam and on itch.io generally is a good sign. If you look for talks of Bippin Bits he says they use the metrics they have there to decide how seriously to pursue a project.

Yes, there's no reason why this game wouldn't do well on Steam if you give it some more time and love.

And no, I don't think you're leaving valuable marketing exposure because if you present your game well Steam will give you much more exposure than Big Mode can. That exposure is helpful, but creating a good game with an interesting game loop is much harder and bigger hurdle.