Slack threads are the worst possible UI ever, so that's not something to aspire to.
Email threading is trivial, nothing magical about it. Most every decent email client will properly thread conversations. Gmail will not, so yes gmail is super painful for long threads. Use a better client.
Email threading is trivial, nothing magical about it. Most every decent email client will properly thread conversations. Gmail will not, so yes gmail is super painful for long threads. Use a better client.