New Tourist VISA change for US citizens

Not sure why you would need to stay out 180 days? That is not even the case now. You just need to leave to any other country and come back. Alternatively, you can apply for an extension of your stay. It is nicely explained online somewhere in this forum. We paid the fee (relatively inexpensive) and took receipt plus completed forms to the correct Federal policy office; we did this in Cuiaba where we are living, and it was very smooth and easy. Got the extension same day and only waited 5 minutes.

Effective June 17, 2019, citizens of the United States, Canada, Australia and Japan will be able to travel to Brazil without a visa. The measure benefits holders of a valid passport traveling for tourism, business, artistic or sports activities. The initiative also covers travelers transiting through Brazil. Visitors will be granted a stay of up to 90 days, with the possibility of an extension for the same period.

When I lived in Brazil, the rule was if you got an extension to your 90 day visa THEN you had to leave and could not come back for 180 days. However, If you left before the 90 days, then you could immediately re-enter for another 90 days. I know this was correct because I had to do it.