COLDCARD and Jade simplify PSPT workflows with full-file transfers. Trezor and Ledger, on the other hand, break it into parts, requiring more steps.
nostr:npub1hea99yd4xt5tjx8jmjvpfz2g5v7nurdqw7ydwst0ww6vw520prnq6fg9v2 sheds some light on the complexities involved in building the Lark app for interacting with hardware wallets in BR089.