I only upvote if something is actually worth upvoting, which basically depends on my mood. I rarely upvote.
I downvote low-effort, some reposts, posting things on comms where they don’t really fit (or they are forcing it to fit, like posting social media screenshots in any of the many memes comms), opinion pieces posted as news, misinformation/propaganda about my country, clickbait… I downvote a lot.
The rest I just read or check and keep moving, I don’t believe in upvoting everything just to make comms feel alive.
Sorry about the content in spanish, but some years ago there were news about someone placing agave or some succulents/cacti in people’s roofs, since some species “absorb” the heat, something along those lines.
Here https://youtu.be/BOjYB7qaESE
Also this plant seems to help refreshing the room in general
https://wikipedia.org/wiki/Dracaena_trifasciata
I haven’t tested them yet since I am just growing my little garden on the roof of my house, but hope something of that helps.