Many good subreddits. r/FIRE and if you're in the UK: r/UKPersonalFinance and r/FIREUK. There is likely similar for US and other countries but I'm less familiar with those.
UKPF is more like SO for finance than HN - occasional interesting stuff, fair amount of arcane situations you're not interested in, and a lot of broadly identical basic questions time and time again. But without flags/marking duplicate/voting to close.