bitcoinfees.earn is a terrible site to use to suggest fees, and this is a perfect example why. 137 sats/vbyte currently puts you with 0.01 MB of the tip of the mempool. Such a fee is maybe warranted if you absolutely must get confirmed in the next block, but for the vast majority of people this is completely unnecessary. A fee of only 5 sats/vbyte will still put you within 0.1 MB of the tip, and is still highly likely to get your transaction confirmed in the next block, and a fee of 3 sats/vbyte will put you 1 MB from the tip and get you confirmed with 2 or 3 blocks. 137 sats/vbyte is a gross over payment in almost all scenarios. A much better fee estimator can be found here: https://mempool.space/

The mempool is currently clearing down to the 1-3 sats/vbyte range, and transactions with fees of 20 sats/vbyte have been confirming in the next block for the last 20 hours or so. OPs transaction should be long confirmed by now.

If you are not in a hurry, then you don't need to pay those fees. Just send at 1 sat/vbyte and be prepared to wait.

I see this option was kind of hidden. If it's set too low doesn't the transaction risk getting rejected or lost in the backlog?

There must be a valid address in the "Pay to" box before the "Max" button will work.

Ah ok that makes sense.
It also was not obvious the request (B) button had to be pressed to populate the address area.
I'm probably a bit dyslexic with UI, and this one is very unintuitive!

Very strange. Does it work within a single wallet? If you hit copy on an address from the "Addresses" tab, can you paste it in to the "Pay to" box on the "Send" tab? Is your clipboard working normally for other programs?