When using the Brave Browser it can occasionally interfere with MetaMask because Brave has its own wallet.
To connect to RNDR, you have to change the browser settings when using the MetaMask plugin in Brave. Go to Settings --> Extensions --> For Web3 provider select --> "MetaMask"
You can check that your RNDR tokens are in your MetaMask wallet by using Etherscan - an Ethereum blockchain explorer - which means that it shows you what’s happening on the Ethereum blockchain in general, which includes what is happening in your wallet.
If you enter your MetaMask address in the search box, you will be able to see the amount of ETH you have in your MetaMask wallet, as well as the various Tokens you possess.
Under the “Overview” section of Etherscan, you can see and select which tokens are in your wallet. Click the drop down and you should see “Render Token (RNDR).” Select that and it will take you to your transaction history for that token.
Private key management is one of the most important aspects of responsible crypto practices. For users with multiple wallets and wallet keys, or those looking to add an extra layer of security, private keys can be imported to another wallet to manage it for you there.
Both your original wallet and the new wallet then have access to the same address on the blockchain. If you do this with a hardware wallet it loses its use case though, which is that this key never has touched a computer and lives in total isolation on that usb stick.