Why such a low success rate? I've sent many 100k transfers and have never had a problem. What's happening to the funds of the other 23%? Are they returned to sender? Or do they just disappear into the network?
Discussion
Still waiting to hear what happens to force closed SATs.
Lighting network looks more like a Ponzi each day
23% failure rate is fuck off high, but is probably due to not enough SATs in the channel.
But if these txns, big or small, happen off chain, then miners won't earn fesles and subsequently will move to more profitable mining
My LND node just decided to stop working and not connect to my existing channels.

"sound money" or some shit
Isn't there a way to backup your channels so you can restore them in case of a situation like this?
Yes you should backup your channels extremely regularly, also watchtowers are useful:
https://docs.lightning.engineering/the-lightning-network/payment-channels/watchtowers
I don't know enough about the intricacies of how it works to conceptualize what's happening. 🤷♂️