Do we have an estimate for when the new tzdb release might be available containing the Brazil rules?

Not really. As a general rule we don't do release schedules.

Is there any way I can request this be updated sooner than later?

Yes, and you just did. :-)

 

My company would ideally prefer to align with a more formal release cadence to get these changes.

You can test or deliver systems based by using the tzdb development repository, which you can get as described in:

https://data.iana.org/time-zones/tz-link.html

It even comes with a version number; run the command 'make version'. It currently has the proposed patches for Brazil.