I found this to be an excellent list of genuinely good capsule hotels in Tokyo. They refer to ones I’ve seen reviewed consistently well by other sources. The following 3 in particular:
9h nine hours
Very modern capsule hotel experience – but found it really, really minimal for my tastes. No frills beyond lockers/showers. The capsules themselves seem like they might be overly claustrophobic as you basically seem to be sleeping in a giant bathtub.
On the top end of the capsule hotel experience with an airline themed experience. especially if you pick a first class cabin. The sliding door doesn’t lock and is almost as much as a hotel makes it a good high-end choice if in a pinch.
Capsule Hotel Anshin Oyado Premier Tokyo
This was a surprise for me. Cheap, but the building comes with all kinds of amenities – including massage chairs, some spa services, and onsen soaking pool. The one in Shibuya seems particularly nice.
What sold me was the individual temperature controls and much more spacious pods. The decor and use of wood feels decidedly like your dad’s era Japan – but looks to be one of the quaint points to me.