What's the easiest way to import a balance from a paper wallet private key (non-QR code) to coinbase? I tried using BRD, but it only accepts QR Code imports.
Use wallet which supports key import. This could be at least Electrum (desktop &amp; mobile).

There are also another wallets supporting so called "sweeping". I can remember precisely that Blockchain.com has this option but I strongly not recommend to use their wallet. 

Just now, I've checked that Samourai Wallet can import private key via QR as soon as allows typing it manually.I don't see the same function in Green Wallet.

That's enough options I think.