You should go to the National Museum Of Emerging Science And Innovation (Miraikan). It has many artistic and educational exhibits, including a demonstration on how networked computers work from scratch with rolling ball machines.
Not sure if it counts as tech but the skytree is extremely cool. It makes the city look like a toy set. I stayed there for way longer than I expected to and went twice over a ten day trip (once during the day and then again at night). I think it’s something people often miss doing.
You can stay in this area for good rates in off season. I walked less than 2 blocks to the tree with great Airbnb hosts 2 times last year. Walking distance to lots of other things too. I walked pretty close to aki from there without thinking about it wondering over a 1/4 day.
Take the elevators up to the top of Yokohama Landmark Tower (https://www.businessinsider.com/the-8-fastest-elevators-in-t...).
Take the Yurikamome train to Odaiba (https://en.wikipedia.org/wiki/Yurikamome).