2 days/week working synchronously with people? Of meetings? I can't remember a time when a project I've worked on needed that to succeed.
I think this set up provides much of the benefit of remote (greater flexibility in personal life commitments) while retaining the necessary components that many often cite for why remote isn't a good option (no face to face meetings). The point however is that it's not supposed to replace either in person or fully remote, but find more choices firms have in their staffing configurations. More choice means there will be greater market fit for both job seekers and employers.
Even for whiteboard discussions, you can buy a literal whiteboard for your work area, hold the meeting over video call, and exchange photos afterward. It's not quite as low friction as walking up to a whiteboard in the office with a coworker, but, at least you know the damn markers will work.
Maintaining WLB is something one needs to be attentive to. Having a dedicated work area as well as maintaining specific work hours (and sticking to them) are key. Other than that, I don't think maintaining WLB at home has to be any tougher than at the office. Kids present special issues, but, if you're a non-WFHer, you already have provisions for the kids during work hours, anyway.
But for a lot of white collar professionals at an associate to mid senior level, there's plenty of work that you should be able to do independently.