feat: try to reproduce an insatiable descriptor error & improve/remove `.unwrap` usage

[oleonardolima]

Describe the enhancement

It's a branch-out issue from both bitcoindevkit/bdk#1448 and bitcoindevkit/bdk#1468, as suggested this issue is specifically meant for trying to reproduce the expected panic! (insatiable descriptor), and fix the .unwrap() usage with appropriate approach.

Use case

Clarifies if the expected panic! ever happens, or it's a totally unexpected situation.

Additional context