I've been twice since 2018, and can't wait to go again.
Akihabara is easy. just walk in to businesses, anime merch is everywhere. If you can't find it there, it doesn't exist.
If you liked Hikaru no Go. you could go to the Nihon Ki-in. It was really cool, and there's a museum in the basement. They even let me sit in the Champion room.
also this...
https://japantour.xyz/2022/06/22/27-real-life-anime-locations-in-tokyo-with-map/