I went to the Lake Ashi collaboration event!
https://www.hakonenavi.jp/groupnews/16197/
Hakone is actually quite easy to get to, but because it's so close, I hadn't visited it before, so in a way, it was a fresh and enjoyable experience.
However, my research was insufficient, and the souvenir shop and cafe in Moto-Hakone were closed that day 😭
But the merchandise itself was available at another location (Togendai), so I was okay.

Oshi no Ko x Lake Ashi - Hey, the shop's closed!? | mentamago's post