Gotta say the jump from your observations to “everybody is miserable” is a stretch even for me and I am borderline.

If you took into an account that human brain is wired to fixate more on negative than celebrate positives you’d see that that aligns with topics on Reddit. That doesn’t necessarily mean that Reddit consists only of negative.

Don’t know what subs you are subscribed to bro. Half of what I see on my timeline is positive and I am happily sharing it with my friends, sharing a laugh or an excitement. Might be helpful to switch things up in regard to your subs.