I'm not position to speak about Microsoft's release plans, but they do have it on their roadmap: https://learn.microsoft.com/ssms/roadmap#arm64-support.
I would also recommend that you take a look at https://developercommunity.visualstudio.com/t/SSMS-21-Support-for-Windows-11-ARM/10850842?%2F10460541= where you 1) can vote for ARM support 2) read a discussion that involves both plain users and program managers from Microsoft.