The tech landscape is infinitely wide at this point. Are you looking to up-skill in your current area or a new area? For me, I always look to younger people. They are always the future for a fast moving industry. In particular, I grew up in the era when you bought huge 500 page books to learn about new technology. In large part, that is dead. You can learn most things online, but not as deep.

Is it possible to mentor young people outside your team? (I say outside your team specifically to avoid manager-worker conflicts.) It is a real eye-opener to spend time with young people. Just watching the way they learn can teach an old dog new tricks.

Last: Is there something on Reddit? If not, how about starting it? I am sure there are lots of devs in their 50s+ looking for somewhere to congregate online.