In July?
The Sakura.
Gardens (gorgeous and will be provide genuine relief in July), proximity to station (and there’s a regular shuttle), and IMHO as much to do nearby as the Westin - but that’s a low bar.
Your wife will not be able to use the whirlpool.
Bear in mind that the communal whirlpool/sauna is a below average facility when compared to other neighbourhood sento and onsen that are easily accessible for just 500yen or so (let’s say 1,000yen for sauna access). Again, your wife will not have access to most of these.

The walk to and from the Westin in July will be gruelling. No shuttle service.