Being in an office also made it clear how much I worked. I was there on most weekends and people noticed.
I'm not saying that that's more important than the benefits of remote, but people absolutely do act like it's a black and white scenario.
I see this claim thrown around frequently as if finding great managers or building a great management culture is an easy thing to do. A great manager in engineering needs to be good at engineering and good at management. It's hard enough to hire for one or the other, let alone both.
1. It is now vitally important to have a clear, mutually agreed upon 30/60/90 program the junior is aware of. These need to be measurable, achievable goals, with specific seniors to reach out to to accomplish. The seniors should also be aware and consenting to play as mentor.
2. Senior engineers should proactively pair program, review, or otherwise attend to the junior as much as the junior is comfortable with. (If the junior's discomfort with mentorship gets in the way of their growth, we need to manage the junior. This shouldn't be mistaken for a junior that doesn't need the mentorship and would understandably find this intense attention to be smothering.)
3. The entire team needs to be aware of onboarding the junior. Expect velocity to slow noticeably for a little bit, until the junior is able to do minor bugfixes and tool building, then slow again when the junior takes meatier projects like features.
Imagine thinking that a Zoom meeting with a few french people is the same as moving to Paris.