In a typical day 0–2 hours of meetings working as a developer independent contractor. I don't count occasional DMing on Slack in that figure.
I think this might be more personality-based than age-related. I'm in my mid-20s and have similar feelings about most meetings. The kind of meetings I like and that are really productive for me are short, for a purpose (there are explicit questions one side has for the other), and with a small number of attendees, for me it's typically 1–3. Working with people you really like to be around I think helps as well.
Which means I can get so much more done, that sit there debating "no, we don't want 6 pop up modals as soon as someone arrives at the website" for a solid hour.
However, I do work with someone else who does the meetings, and we have constant back and forth for the whole day.
I've been on teams that average 3 hours per day. Honestly I'd bring a laptop and work through them. If there's that much information to distribute, I probably don't care about most of it.
Healthy social time would depend on how well you get along with the people.
I'd say a majority of time would with someone / people you get along very well with would be the most healthy.