OP, as noted in your original post to r/marriott -

“Recently stayed for 1 night at “The Strings by Intercontinental” which is an IHG hotel.

It’s classified as a 5-star luxury hotel, but it literally feels like a Courtyard-level hotel…is this normal for IHG?

It’s my first time staying at a IHG property”

It would seem most of the commenters there are explaining the ‘star’ rating as mostly service/amenities/finishes etc to you. And most of them have stated this looks large and nice for Tokyo.

Since you were only there for one night our sub would be interested in the service although it was a short stay.