So, I think this novel is on RoyalRoadL. It's about 2 brothers, one a genius and the other "thrash" but he's only very low-key. The "thrash" one has the power to absorb or use every type of magic.
https://royalroadl.com/fictions/sea...atus=ALL&orderBy=popularity&dir=desc&type=ALL Sounds like something on this list
So what you are looking for is a novel, suspected to be from RRL, that is in a magic type world where the main focus seems to be 2 brothers of which one is seen as a Genius while the other as trash The trashy brother however has a special ability that allows his to absorb magic and use it himself. Do you remember any other significant details?