I can invest around 100k+ on equipments or hardware which are related to mining + free electricity I have
Then which coin is best to mine
Well,.. with $100K you can buy 122 Antminers T17 which will give you ~61000 Th/s.
With free energy this can be translated into $905/day acording to whattomine.com at current Bitcoin price of $8650.
Keep in mind that Bitcoin halving is near and this will translate into half of that after May 2020.
Since the halving is near, you can look at coins that already had it's halving i.e. Litecoin.