I don't see bad UX anywhere. It seems most wallet interfaces are at least as much and usually more usual friendly (less clutter) than any typical online banking interface. How much simpler can it get?

That said, the challenge (if one is to custody and send his own on-chain coins) is not at the UX level, which is a frontend. A user should spend some time on mastering basic concepts of Bitcoin address, seed phrase, transactions, UTXO and how these concepts link together. No matter the front-end, these are absolutely the bare minimum to understand. Unless one is clear about what is a bitcoin, what it means to receive it, and what causes it to be sent/spent, he will inevitably make some mistake-thus blowing up his entire fund (lost keys, sent to wrong destination or gave away seed phrase to some customer support guy). Then he will go on for his whole life telling people Bitcoin is a scam.