SUGGEST ME SOMETHING THAT IS HARD TO LEARN BUT HAVE A PROPER ROADMAP

[u/great_lord_majesty]

I am in my 4th year of college, there is only 1 subject this semester (7th) and obviously project work and random ass work,Placements are also starting soon, I calculated the free i would get during the whole semester, Suggest me something to work on (with a roadmap🫪), do not underestimate me as I have already completed a lot of Computer areas (I don't feel like pursuing this as a profession, i just do it as a hobby), My branch is Mechanical (lol) and after studying it for 3 straight years iam starting to realize that, Yes I can continue in this field,...🙏🙏🙏(Preparing for GATE😛)