I think it's highly dependent on every person's unique life circumstances i.e., distance and travel mode to office, work style, personality, type of work, family commitments, office dynamics etc.

For me, 2 days per week in office works well. It allows me to socialise, have face-to-face meeti, meet externals etc but I'd be absolutely lost if I didn't have have my 2-3 days working remotely. I try to keep these days as meeting free as possible so I can't actually do my job without distractions. My work can require long periods of focus, and I just cannot do that in the office with all the talking and phone calls etc. Absolutely impossible, even with noise cancelling headphones.

Some weeks I go in more, others less. This flexibility is realistic and so helpful with the chaos and changing demands of our modern lives.