I haven't found a game yet which which implements that concept. The closest is probably Noita (https://noitagame.com/). But I would like an isometric view (or third-person view in 3d world) and the spells effects use some kind of particle animation within that world; as opposed as simple pixels in a 2d platformer.
I don't have a background in game development, so I don't know where to start. I'd like to discuss the idea and potentially have some devs build a prototype to build a prototype and see if it's actually fun to play with. How do I reach for studios and/or indie devs ? Are there good gamedevs forums for that? I am willing to pay for contracts to build some prototypes or fund a whole game if things are promising (let's say ranging from 50k to 1-2M).
My suggestion would be to find and hire someone relatively senior with experience setting up game teams. There’s a bunch of Discords out there as well as some industry trade websites that host hiring ads. LinkedIn is a good bet as well and for what you want to do working with a recruiter that specialises in game jobs is probably a good bet as well.
In general people with an idea but no experience are treated with quite a bit of skepticism even if they have a budget! Getting someone with good experience on board to lead things will go a long way to help with that.
I think the answer to the question is already in your post. You said noita is pretty close so why not just play that? That's where you start.
Now, if you want some unsolicited financial advise do not dare spending 50k-2000k on a game development project if you don't have the skills/desire to work on it yourself
> 50k to 1-2M
Is this USD (or comparable: EUR, CHF, whatever you have)? With this money you could pick your favorite indie game dev studio, and ask for a quote.