All is well here on Ubuntu 23.10, Firefox (Snap) 122.0 and 'Teams Classic' as per Office 365, no special opt-ins (like Insider Program) or opt-outs. There are

All is well here on Ubuntu 23.10, Firefox (Snap) 122.0 and 'Teams Classic' as per Office 365, no special opt-ins (like Insider Program) or opt-outs. There are many different versions of Teams, though, and whatever I'm getting via https://teams.microsoft.com/ https://teams.microsoft.com/ may be very different from what you're seeing. You may want to check if things work better via Chrom(e|ium) first, as that's a low-effort thing?