I suppose Senior developers, my self included, enjoy fast paces straight to the point learning resources. One of my favorite websites is https://egghead.io/ but some people do complain about behind a bit too fast. Overall, there is heaps of great tutorial on youtube.

If you're looking for an online community mostly you'll be facing many people who are learning how to code. I would choose a specific software and look for paid/free courses that have a community on slack/discord. Regardless of your age, sometimes changing the company you work with can help a lot because you'll on the hunt for other companies using modern stacks. You could also try to convince your company to adopt new tech. Do not be afraid to join younger communities, there days people don't really care about your age as long as you have things in common and a beginner spirit.