How many devices can I connect to a partner exchange?
The device limit is currently 4 per partner exchange.
If you are able to verify with both Uphold and Gemini you would effectively have 8 device slots. However if you were to connect the same device/installation of Brave to both exchanges that would be one slot gone from each.
If you can only verify with one partner exchange based on the country in which you live (or not having identity documents required by one of the exchanges) you would only have 4 slots total, and if you cannot currently verify with both exchanges you have zero slots.
Be aware that devices can only be disconnected from a partner exchange from Brave's side - they will continue to be counted against each partner exchange's limit even after disconnecting in Brave.
The Brave team have said they are working on a way to allow proper disconnection of devices from partner exchanges. No ETA has been given yet, and progress has only just started on the tool. [Current August 30 2021]
Eventually the upcoming Brave Wallet will allow users to withdraw without a partner exchange, but it will still require KYC. At the moment there is no way to know what countries are supported or which documents will be required for the KYC that the Brave Wallet will require. [Current September 7 2021]