I wish you could have got it will full colour joycons, life is so grey, boring and flat these days.I get what you mean about the design. It's kind of a shame that it's not a bit more different to the Switch, but I get that they didn't want to depart from the handheld aspect, given that's one of the most popular aspects of the original.
I'd love to go to the Nintendo museum! You lucked out there with an original DS. I've still got my 3DS XL and charged it up the other day. It looked a lot more dated than I remembered, but it's still fun to play games on it.
We went to the museum not long after it opened and it was a nightmare getting two tickets. I'm glad I went but it's nothing to write home about. One level is a collection of things to look at (the best bit was probably the video screens showing the same game in different generations but you could watch that on youtube) and the bottom level was big controllers to play on and some of their old toys to play with. The best was probably the real life baseball. The shop had some cool unique things in. The cafe was a normal burger place with a bit of theming. There were some workshops but didn't feel like making a deck of cards. Much better things to do in Kyoto.