You are not being treated like a team member.
I would question whether it's appropriate that your team mates have a private meeting without you at all, let alone one where they make insulting jokes about you.
My team mates like to have a private zoom meeting before our daily meeting where they speak in their native tongue
This seems inappropriate. If you're part of the team you should not be excluded from a meeting. What's the point of having a meeting that excludes one team member ?
I joined in by mistake a while back and got to hear a gross joke about my possible sexual orientation and nationality and other gossip.
An odd way for your team mates to use a private meeting that excludes you. I would again say this suggests you are not being brought into the team at all and making such a joke at a meeting is quite wrong.
In no meeting should remarks of this sort be made about a work colleague. It's disgusting behavior.
I kept joining early, mostly because the tool we are using is flaky and sometimes it takes some time get in, and the Scrum master is vocal about being late and I usually catch 1-2 minutes of their conversation.
This makes it sound like the scrum master is actually letting them make insulting jokes about you. That's quite appalling if it's the case.
The problem I see here is that you are not being treated as an equal team member, not that they don't speak in English while they're making crude "jokes" about you or you cannot follow a technical discussion they've deliberately excluded you from (and why exclude you at all ?).