I find that I've had more meaningful engagement within decetralised spaces than the centralised ones. Sadly the corpos the type of engagement doesn't seem to matter too much as long as it's engagement on their site and not someone else's. I felt that same pressure to be honest.

You're right about the good use cases, it's nice within the marginalised communities / subreddits but outside of them it's not so great. Sometimes you want to engage in other communities in peace as well so I guess it comes down to moderation but I understand the karma points is a barrier to entry for trolls.

Community level point counts might not be too bad tbh because like you said, it would be a way of stopping people from using other communties that might not have the best intentions to farm karma so they're not in minus numbers. To be honest, a count did span across a site it would be a nice feature to have a breakdown as to what communities that positive and negative karma comes from..