Student perspective here. Big fan of Slack, worked great during my Master’s project. Prefer it over Discord, which focuses more on voice chat, due to app integrations and it being a bit more ‘professional’.

As for task management, I feel it might be best to leave it up to the students? If I had to choose one tool for everyone, I would suggest Notion. That would allow the students to manage their projects in their own way (to-do, kanban, ELN/journal etc.) but still all integrated into one tool.