The unexplored outcome of hybrid is that there's no such thing as hybrid.
In a hybrid model, you come into the office and find people sitting in chairs with a headphone on. Because they're just as much in calls as they were at home. Because part of the meeting participants on any given day is not there.
Hence, this nice physical face-to-face meeting, a supposed benefit of returning to the office, does not materialize.
Well, perhaps you'll at least do some ad-hoc brainstorming with your colleague at the coffee machine. Sure, but you need to put the outcome of that in writing...for the people that are not there.
Hence, this mode of virtual working cannot be undone. You can't do a "little" virtual working. When you come into the office you largely continue to work as if from home. Perhaps without the sweatpants.
For the record, I'm not anti-office. I enjoy the socializing, lunch walks, etc. And in our increasingly touchless home-based society, it's not that bad of a deal to get out of the house for 2 or 3 days a week. Finally, we should empathize with juniors. In my experience, remote mentoring is a piss poor substitute for the real thing.