You could always try a subreddit like r/math [0]. I’ve found the mathematics stackexhange site helpful for questions or just browsing [1] it even has a chat [2] which is nice if you have a question that’s quick or not really that useful to anyone else. On reddit and stack exchange you can also do some form of sorting by all time popularity which can be interesting sometimes.
[0]: https://www.reddit.com/r/math
[1]: https://math.stackexchange.com
[2]: https://chat.stackexchange.com/rooms/36/mathematics