after some thinking and experimenting, looks like i found the way to make good, balanced research system for my game.
Firstly, to do some reaserach you require special metal for each try (it goes on top of couldron)
Then you can add another metal as catalyst (it goes on left side, before step counter), it wil unlock random step even if you don't match anything
Then goes grow-like matching game. You can't use the same element more than 1 time now. Also if you unlock step, you have to follow it, or next researches will not work
After selecting all elements click "research"
When you finish the research it will unlock new recipe for cauldron or some other stuff
short vid about new system
*thanks to @benjamin and @wan for ideas that helped me to make new system. *
@wan i made test version (there is a bug that you can't buy elements while in research mode and only 1 research can be made)
and no, even with catalyst, you can't use random combination
test version
The new research system seems a bit more intricate indeed, but if I get it the only purpose of catalysts is just to gain some time/to think less. Like, it allows to press randomly all 8 buttons and still have a guaranteed unlock, right? If so it still sounds a bit flawed. Though I guess we'd have to see how this new version of the mini-game integrates with the rest.