Slack is still trash.
I segregate browsers by using different Linux users for different tasks (slack, Facebook, general, etc) which works well with my similarly bespoke workflow. The problem with this arrangement is that When Firefox has pending system upgrades it requires all browsers be closed and reopened.
I’m curious about your productivity hack though, I use a grid keyboard layout with ~20 workspaces grouped to four windows for each task/project and one set to emails/fb/slack