VISA BRAZIL MARRY BRAZILIAN PANAMA

There are ways to have a stable union in BR, then applying for a CRNM (permanent resident).
Now it is a detailed process and you will need many documents translated (official translation), legalized/apostilled . You will need a resident (not a hotel) and have a utility bill in your name and other documents.
It is easier to marry in Panama and then register same with the BR Consulate. You will still need a visa/waiver to enter.
As you are aware the BR borders are closed. The Policia Federal (PF) is also not accepting and permanent visa applications. (You have to apply in Brazil for such)
You can go to PF website and review the documents required. There is the federal (your passport country) background check which can not be more than 90 days old.
Right now, review the documents required and work on them while all the health issues exist. Once returning to normal you will better prepared.

There's no problem with you and your fiancée getting married in Panama.  Register your marriage at the Brazilian Consulate there with your Panamanian marriage certificate,  and it will be recognized in Brazil.   Once you're married, you can request a VITEM XI temporary visa for family reunion,  which will give you as much as a year in Brazil to obtain your CRNM.  You'll still need all the other documents on the Federal Police list.

Fantastic advice !
Thank you. I have my home work cut out for me.

Thank you very much for your extensive reply. As you say, now with the quarantine in place, I might as well use this time to get prepared. Thanks!