since the beginning of the year i've been using elevate (linked). it gives you a few games to do every day and has been a quick and easy way to remind myself i do in fact have a working brain
aside from that, just READ!! i know its a lame answer but i truly feel there's no better way to combat brain rot and increase your attention span. you don't even have to read anything serious - whatever you find fun or interesting, read about it instead of watching tiktoks/youtube videos.
